Tue Apr 6,12:24 AM ET
By Michael Byrnes
SYDNEY (Reuters) - If Australia replaces even a small percentage of its plastic bags with biodegradable carriers made from grains, it would boost demand for wheat and other grains by 500 percent over 15 years.
"Alternative uses for starches are just going through the roof. (It) is absolutely massive," Kim Hatton, analyst with Pocknee and Associates Consulting, who prepared a report for the Australian grains industry, told Reuters.
Old fashioned starch is an emerging star as a replacement for petrochemicals in biodegradable plastics, tennis shoes, disposable knives, forks and plates, edible crayons, wheat-based kitty litter, and much more
Grains are also seen as a major new raw material in Australia for automobile fuel, pharmaceuticals, livestock feed and meat substitutes.
A report by Pocknee for Australia's annual Grains Week conference last week forecast that demand for the country's grains would jump massively, to 179 million tons in 2020 from around 40 million at present.
Demand for cereals for starch production alone was seen rising to 56.6 million tons in 2020 from nil in 2005. Demand for cereals for ethanol production by 2020 was forecast to rise to 17.6 million tons from 165,000 tons in 2005, while total demand for cereals for emergent uses was seen jumping to 120.7 million tons from only 501,000 tones in 2005.
The forecasts stunned major players in Australia's normally divisive grains industry into pledges of co-operation to produce efficiencies and increased yields to boost supply.
Wednesday, September 22, 2010
Procedure relating to import of Plastic Waste/Scrap.
Government of India
Ministry of Commerce & Industry
Department of Commerce
Directorate General of Foreign Trade
Udyog Bhavan New Delhi
Policy Circular No. 20 /2002-2007 Dated March 12, 2003
To
All Licensing Authorities,
All Commissioners of Customs,
All concerned.
Subject : Procedure relating to import of Plastic Waste/Scrap.
Attention is invited to Public Notice No.392 (PN)/92-97 dated 1.1.1997 according to which import of Plastic Waste/Scrap (except PET Bottle Waste/Scarp) and animal dung or animal excreta shall not, be permitted, except against a license. Applicants while submitting the application as per provisions laid down in para 1(iv) of the said public notice shall adhere to all guidelines / conditions of this public notice. They shall also furnish the following additional information / details while submitting the application to DGFT: -
i) copy of the Industrial approval (SSI Registration / IEM / Industrial Licence etc) alongwith the date of commencement of commercial production duly approved by competent authority. Copy of the valid Pollution control clearance certificate (both for air & water) from State Pollution Control Board where the unit is located.
ii) Brief details of manufacturing process for the recycling plant and the finished articles (if recycled material is consumed captive), production equipment installed with the date of installation (both imported & indigenous) alongwith specifications/rated capacity/production capacity with calculations duly certified by C.E. Rated/production capacity will be worked out as 20 hrs per day/330 days in a year.
iii) For the existing unit the details of consumption (separately 91 to 2001-02 duly certified by Chartered Accountant, along with details of import licence obtained. Details should be furnished for different types of plastic waste/scrap separately.
iv) Specific name, type specification & source of import of plastic waste/scrap alongwith the declaration by the importer that, the plastic waste/scrap being imported by them and for which the clearance is sought strictly conforms to the description/definition in accordance with Public Notice No.392 dated 1.1.1997.
2. The application shall be examined for grant of import license on the basis of the above information furnished by the firm. Further the entitlement of Plastic Waste/scrap (other than Acrylic Plastic Waste/Scrap) will be determined on the basis of following criteria/ guidelines as suggested by the Department of C&PC:-
a) The import of Plastic waste/scrap (other than Acrylic Plastic waste/scrap) may be considered on the 50% of the installed capacity of the production machineries taking into account production equipment rated capacity per hour for 20 hours/day and 330 days in a year.
b) The entitlement of Acrylic Plastic waste/scrap may be determined taking into consideration the best consumption in a particular financial year during the period 1990-91 to 2001-02.
c) The units set up after 19.6.1998 (i.e. date on which EPB took decision not to permit import of plastic scrap even for EOUs, and that no new units will be permitted to be set up) shall not be considered for recommending import of plastic waste/scrap.
3. The Ministry of Environment & Forest will continue to furnish their comments as per the guidelines contained in Public Notice No.392 dated 1.1.1997.
4. All other provision contained in the aforesaid public notice shall remain in force and will be strictly complied by all the applicants who wish to submit application to DGFT for grant of import licence for import of plastic waste/scrap.
This issues with the approval of Director General of Foreign Trade
S.K. Bhardwaj
Deputy Director
Ministry of Commerce & Industry
Department of Commerce
Directorate General of Foreign Trade
Udyog Bhavan New Delhi
Policy Circular No. 20 /2002-2007 Dated March 12, 2003
To
All Licensing Authorities,
All Commissioners of Customs,
All concerned.
Subject : Procedure relating to import of Plastic Waste/Scrap.
Attention is invited to Public Notice No.392 (PN)/92-97 dated 1.1.1997 according to which import of Plastic Waste/Scrap (except PET Bottle Waste/Scarp) and animal dung or animal excreta shall not, be permitted, except against a license. Applicants while submitting the application as per provisions laid down in para 1(iv) of the said public notice shall adhere to all guidelines / conditions of this public notice. They shall also furnish the following additional information / details while submitting the application to DGFT: -
i) copy of the Industrial approval (SSI Registration / IEM / Industrial Licence etc) alongwith the date of commencement of commercial production duly approved by competent authority. Copy of the valid Pollution control clearance certificate (both for air & water) from State Pollution Control Board where the unit is located.
ii) Brief details of manufacturing process for the recycling plant and the finished articles (if recycled material is consumed captive), production equipment installed with the date of installation (both imported & indigenous) alongwith specifications/rated capacity/production capacity with calculations duly certified by C.E. Rated/production capacity will be worked out as 20 hrs per day/330 days in a year.
iii) For the existing unit the details of consumption (separately 91 to 2001-02 duly certified by Chartered Accountant, along with details of import licence obtained. Details should be furnished for different types of plastic waste/scrap separately.
iv) Specific name, type specification & source of import of plastic waste/scrap alongwith the declaration by the importer that, the plastic waste/scrap being imported by them and for which the clearance is sought strictly conforms to the description/definition in accordance with Public Notice No.392 dated 1.1.1997.
2. The application shall be examined for grant of import license on the basis of the above information furnished by the firm. Further the entitlement of Plastic Waste/scrap (other than Acrylic Plastic Waste/Scrap) will be determined on the basis of following criteria/ guidelines as suggested by the Department of C&PC:-
a) The import of Plastic waste/scrap (other than Acrylic Plastic waste/scrap) may be considered on the 50% of the installed capacity of the production machineries taking into account production equipment rated capacity per hour for 20 hours/day and 330 days in a year.
b) The entitlement of Acrylic Plastic waste/scrap may be determined taking into consideration the best consumption in a particular financial year during the period 1990-91 to 2001-02.
c) The units set up after 19.6.1998 (i.e. date on which EPB took decision not to permit import of plastic scrap even for EOUs, and that no new units will be permitted to be set up) shall not be considered for recommending import of plastic waste/scrap.
3. The Ministry of Environment & Forest will continue to furnish their comments as per the guidelines contained in Public Notice No.392 dated 1.1.1997.
4. All other provision contained in the aforesaid public notice shall remain in force and will be strictly complied by all the applicants who wish to submit application to DGFT for grant of import licence for import of plastic waste/scrap.
This issues with the approval of Director General of Foreign Trade
S.K. Bhardwaj
Deputy Director
Friday, September 17, 2010
BIO DEGRADABLE PLASTICS – AN INTRODUCTION
1. PLA - Poly Lactic Acid:
Poly(lactic acid) or polylactide (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the United States) or sugarcanes (in the rest of world). Although PLA has been known for more than a century, it has only been of commercial interest in recent years, in light of its biodegradability. The name "polylactic acid" is to be used with caution, not complying to standard nomenclatures (such as IUPAC) and potentially leading to ambiguity (PLA is not a polyacid (polyelectrolyte), but rather a polyester)
Synthesis:
Bacterial fermentation is used to produce lactic acid from corn starch or cane sugar. However, lactic acid cannot be directly polymerized to a useful product, because each polymerization reaction generates one molecule of water, the presence of which degrades the forming polymer chain to the point that only very low molecular weights are observed. Instead, lactic acid is oligomerized and then catalytically dimerized to make the cyclic lactide monomer. Although dimerization also generates water, it can be separated prior to polymerization. PLA of high molecular weight is produced from the lactide monomer by ring-opening polymerization using most commonly a stannous octane catalyst, but for laboratory demonstrations tin(II) chloride is often employed. This mechanism does not generate additional water, and hence, a wide range of molecular weights is accessible.
Polymerization
Polymerization of a racemic mixture of L- and D-lactides usually leads to the synthesis of poly-DL-lactide (PDLLA) which is amorphous. Use of stereospecific catalysts can lead to heterotactic PLA which has been found to show crystallinity. The degree of crystallinity, and hence many important properties, is largely controlled by the ratio of D to L enantiomers used, and to a lesser extent on the type of catalyst used.
Properties:
Due to the chiral nature of lactic acid, several distinct forms of polylactide exist: poly-L-lactide (PLLA) is the product resulting from polymerization of L,L-lactide (also known as L-lactide). PLLA has a crystallinity of around 37%, a glass transition temperature between 60-65 °C, a melting temperature between 173-178 °C and a tensile modulus between 2.7-16 GPa
PLA has similar mechanical properties to PTFE polymer, but has a significantly lower maximum continuous use temperature.
Polylactic acid can be processed like most thermoplastics into fiber (for example using conventional melt spinning processes) and film. The melting temperature of PLLA can be increased 40-50 °C and its heat deflection temperature can be increased from approximately 60°C to up to 190 °C by physically blending the polymer with PDLA (poly-D-lactide). PDLA and PLLA form a highly regular stereocomplex with increased crystallinity. The temperature stability is maximised when a 50:50 blend is used, but even at lower concentrations of 3-10% of PDLA, there is still a substantial improvement. In the latter case, PDLA acts as a nucleating agent, thereby increasing the crystallization rate. Biodegradation of PDLA is slower than for PLA due to the higher crystallinity of PDLA. PDLA has the useful property of being optically transparent.
Applications:
Stereocomplex blends of PDLA and PLLA have a wide range of applications, such as woven shirts (ironability), microwavable trays, hot-fill applications and even engineering plastics (in this case, the stereocomplex is blended with a rubber-like polymer such as ABS). Such blends also have good form-stability and visual transparency, making them useful for low-end packaging applications. Progress in biotechnology has resulted in the development of commercial production of the D enantiomer form, something that was not possible until recently.
PLA is currently used in a number of biomedical applications, such as sutures, stents, dialysis media and drug delivery devices. It is also being evaluated as a material for tissue engineering. Because it is biodegradable, it can also be employed in the preparation of bioplastic, useful for producing loose-fill packaging, compost bags, food packaging, and disposable tableware. In the form of fibers and non-woven textiles, PLA also has many potential uses, for example as upholstery, disposable garments, awnings, feminine hygiene products, and nappies.
PLA has been used as the hydrophobic block of amphiphilic synthetic block copolymers used to form the vesicle membrane of polymersomes.
PLA is a sustainable alternative to petrochemical-derived products, since the lactides from which it is ultimately produced can be derived from the fermentation of agricultural by-products such as corn starch or other carbohydrate-rich substances like maize, sugar or wheat.
PLA is more expensive than many petroleum-derived commodity plastics, but its price has been falling as production increases. The demand for corn is growing, both due to the use of corn for bioethanol and for corn-dependent commodities, including PLA.
PLA has also been developed in the United Kingdom to serve as sandwich packaging.
PLA has also been used in France to serve as the binder in Isonat Nat’isol, an hemp fiber building insulation.
PLA is used for biodegradable and compostable disposable cups for cold beverages, the lining in cups for hot beverages, deli containers and clamshells for food packaging.
2. CELLOPHANE
Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, and bacteria makes it useful for food packaging. Cellophane is in many countries a registered trade mark of Innovia Films Ltd, Cumbria, UK
Production:
Cellulose from wood, cotton, hemp, or other sources is dissolved in alkali and carbon disulfide to make a solution called viscose, which is then extruded through a slit into a bath of dilute sulfuric acid and sodium sulfate to reconvert the viscose into cellulose. The film is then passed through several more baths, one to remove sulfur, one to bleach the film, and one to add glycerin to prevent the film from becoming brittle.
A similar process, using a hole (a spinneret) instead of a slit, is used to make a fibre called rayon. Chemically, cellophane, rayon and cellulose are polymers of glucose and contain the chemical elements carbon, hydrogen, and oxygen.
Cellulose film has been manufactured continuously since the mid-1930s and is still used today. As well as packaging a variety of food items, there are also industrial applications, such as a base for such self-adhesive tapes as Sellotape and Scotch Tape, a semi-permeable membrane in a certain type of battery, as dialysis tubing (Visking tubing) and as a release agent in the manufacture of fibreglass and rubber products. The word "cellophane" has become genericized in the US, and is often used informally to refer to a wide variety of plastic film products, even those not made of cellulose. However, in the UK and in many other countries it is still a registered trademark and the property of Innovia Films Ltd.
Cellophane sales have dwindled since the 1960s due to use of alternative packaging options, and the fact that viscose is becoming less common because of the polluting effects of carbon disulfide and other by-products of the process used to make it. However, the fact that cellophane is 100% biodegradable has increased its popularity as a food wrapping. Cellophane is the most popular material for manufacturing cigar packaging; its permeability to moisture makes cellophane the perfect product for this application as cigars must be allowed to "breathe" while in storage.
When placed between two plane polarizing filters, cellophane produces prismatic colors due to its birefringent nature. Artists have used this effect to create stained glass-like creations that are kinetic and interactive.
3. PLASTARCH MATERIAL
Plastarch Material (PSM) is a biodegradable, thermoplastic resin. It is composed of starch combined with several other biodegradable materials. The starch is modified in order to obtain heat-resistant properties, making PSM one of few bioplastics capable of withstanding high temperatures. PSM began to be commercially available in 2005.
PSM is stable in the atmosphere, but biodegradable in compost, wet soil, fresh water, seawater, and activated sludge where microorganisms exist. It has a softening temperature of 257°F (125°C) and a melting temperature of 313°F (156°C).
It is also hygroscopic. The material has to be dried in a material dryer at 150°F (66°C) for five hours or 180°F (82°C) for three hours. For injection molding and extrusion the barrel temperatures should be at 340° +/- 10°F (171°C) with the nozzle/die at 360°F (182°C).
Due to how similar PSM is to other plastics (such as polypropylene and CPET), PSM can run on many existing thermoforming and injection molding lines. PSM is currently used for a wide variety of applications in the plastic market, such as food packaging and utensils, personal care items, plastic bags, temporary construction tubing, industrial foam packaging, industrial and agricultural film, window insulation, construction stakes, and horticulture planters.
Since PSM is derived from a renewable resource (corn), it has become an attractive alternative to petrochemical-derived products. Unlike plastic, PSM can also be disposed of through incineration, resulting in non-toxic smoke and a white residue which can be used as fertilizer.
4.Polycaprolactone (PCL)
is a biodegradable polyester with a low melting point of around 60°C and a glass transition temperature of about −60°C. PCL is prepared by ring opening polymerization of ε-caprolactone using a catalyst such as stannous octanoate. The most common use of polycaprolactone is in the manufacture of speciality polyurethanes. Polycaprolactones impart good water, oil, solvent and chlorine resistance to the polyurethane produced.
This polymer is often used as an additive for resins to improve their processing characteristics and their end use properties (e.g., impact resistance). Being compatible with a range of other materials, PCL can be mixed with starch to lower its cost and increase biodegradability or it can be added as a polymeric plasticizer to PVC.
Polycaprolactone is also used for splinting, modeling, and as a feedstock for prototyping systems such as a RepRap, where it is used for Fused Filament Fabrication (similar to the Stratasys' Fused Deposition Modeling or FDM technique).
Polymerization
Biomedical applications:
PCL is degraded by hydrolysis of its ester linkages in physiological conditions (such as in the human body) and has therefore received a great deal of attention for use as an implantable biomaterial. In particular it is especially interesting for the preparation of long term implantable devices, owing to its degradation which is even slower than that of polylactide.
PCL is an Food and Drug Administration (FDA) approved material that is used in the human body as (for example) a drug delivery device, suture (sold under the brand name Monocryl or generically), or adhesion barrier. It is being investigated as a scaffold for tissue repair via tissue engineering, GBR membrane. It has been used as the hydrophobic block of amphiphilic synthetic block copolymers used to form the vesicle membrane of polymersomes.
A variety of drugs have been encapsulated within PCL beads for controlled release and targeted drug delivery which have been peer reviewed
The major impurities in the medical grade are toluene (<890 ppm, usually about 100 ppm) and tin (<200ppm).
In odontology or dentistry (as composite named Resilon), it is used in root canal filling. It performs like gutta-percha, has the same handling properties, and for retreatment purposes may be softened with heat, or dissolved with solvents like chloroform. Similar to gutta-percha, there are master cones in all ISO sizes and accessory cones in different sizes available. The major difference between the polycaprolactone-based root canal filling material (Resilon and Real Seal) and gutta-percha is that the PCL-based material is biodegradable but the gutta-percha is not. There is lack of consensus in the expert dental community as to whether a resorbable root canal filling material, such as Resilon or Real Seal is desirable.
Hobbyist and Prototyping:
PCL also has many applications in the hobbyist market. Some brand names used in selling it to this market are Shapelock and Friendly Plastic in the US, and Polymorph in the UK. It has physical properties of a very tough, nylon-like plastic that melts to a putty-like consistency at only 60°C. PCL's specific heat and conductivity are low enough that it is not hard to handle at this temperature.
This makes it ideal for small-scale modeling, part fabrication, repair of plastic objects, and rapid prototyping where heat resistance is not needed. Though molten PCL readily sticks to many other plastics, if the surface is cooled, the stickiness can be minimized while still leaving the mass pliable.
5. Polyglycolide or Polyglycolic acid (PGA):
is a biodegradable, thermoplastic polymer and the simplest linear, aliphatic polyester. It can be prepared starting from glycolic acid by means of polycondensation or ring-opening polymerization. PGA has been known since 1954 as a tough fiber-forming polymer. Owing to its hydrolytic instability, however, its use has initially been limited. Currently polyglycolide and its copolymers (poly(lactic-co-glycolic acid) with lactic acid, poly(glycolide-co-caprolactone) with ε-caprolactone, and poly (glycolide-co-trimethylene carbonate) with trimethylene carbonate) are widely used as a material for the synthesis of absorbable sutures and are being evaluated in the biomedical field
Synthesis:
Polyglycolide can be obtained through several different processes starting with different materials:
1. polycondensation of glycolic acid;
2. ring-opening polymerization of glycolide;
3. solid-state polycondensation of halogenoacetates;
4. acid catalyzed reaction of carbon monoxide and formaldehyde
Polycondensation of glycolic acid is the simplest process available to prepare PGA, but it is not the most efficient because it yields a low molecular weight product. Briefly, the procedure is as follows: glycolic acid is heated at atmospheric pressure and a temperature of about 175-185°C is maintained until water ceases to distill. Subsequently, pressure is reduced to 150 mm Hg, still keeping the temperature unaltered for about two hours and the low MW polyglycolide is obtained.
The most common synthesis used to produce a high molecular weight form of the polymer is ring-opening polymerization of "glycolide", the cyclic diester of glycolic acid. Glycolide can be prepared by heating under reduced pressure low MW PGA, collecting the diester by means of distillation. Ring-opening polymerization of glycolide can be catalyzed using different catalysts, including antimony compounds, such as antimony trioxide or antimony trihalides, zinc compounds (zinc lactate) and tin compounds like stannous octoate (tin(II) 2-ethylhexanoate) or tin alkoxides. Stannous octoate is the most commonly used initiator, since it is approved by the FDA as a food stabilizer. Usage of other catalysts has been disclosed as well, among these are aluminum isopropoxide, calcium acetylacetonate, and several lanthanide alkoxides (e.g. yttrium isopropoxide).The procedure followed for ring-opening polymerization is briefly outlined: a catalytic amount of initiator is added to glycolide under a nitrogen atmosphere at a temperature of 195°C. The reaction is allowed to proceed for about two hours, then temperature is raised to 230°C for about half an hour. After solidification the resulting high MW polymer is collected
Another procedure consists in the thermally induced solid-state polycondensation of halogenoacetates with general formula X-—CH2COO-M+ (where M is a monovalent metal like sodium and X is a halogen like chlorine), resulting in the production of polyglycolide and small crystals of a salt. Polycondensation is carried out by heating an halogenoacetate, like sodium chloroacetate, at a temperature between 160-180°C, continuously passing nitrogen through the reaction vessel. During the reaction polyglycolide is formed along with sodium chloride which precipitates within the polymeric matrix; the salt can be conveniently removed by washing the product of the reaction with water.
PGA can also be obtained by reacting carbon monoxide, formaldehyde or one of its related compounds like paraformaldehyde or trioxane, in presence of an acidic catalyst. In a carbon monoxide atmosphere an autoclave is loaded with the catalyst (chlorosulfonic acid), dichloromethane and trioxane, then it is charged with carbon monoxide until aspecific pressure is reached; the reaction is stirred and allowed to proceed at a temperature of about 180°C for two hours. Upon completion the unreacted carbon monoxide is discharged and a mixture of low and high MW polyglycolide is collected
Physical properties:
Polyglycolide has a glass transition temperature between 35-40 °C and its melting point is reported to be in the range of 225-230 °C. PGA also exhibits an elevated degree of crystallinity, around 45-55%, thus resulting in insolubility in water. The solubility of this polyester is somewhat unique, in that its high molecular weight form is insoluble in almost all common organic solvents (acetone, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran), while low molecular weight oligomers sufficiently differ in their physical properties to be more soluble. However, polyglycolide is soluble in highly fluorinated solvents like hexafluoroisopropanol (HFIP) and hexafluoroacetone sesquihydrate, that can be used to prepare solutions of the high MW polymer for melt spinning and film preparation. Fibers of PGA exhibit high strength and modulus (7 GPa) and are particularly stiff.
Degradation:
Polyglycolide is characterized by hydrolytic instability owing to the presence of the ester linkage in its backbone. The degradation process is erosive and appears to take place in two steps during which the polymer is converted back to its monomer glycolic acid: first water diffuses into the amorphous (non-crystalline) regions of the polymer matrix, cleaving the ester bonds; the second step starts after the amorphous regions have been eroded, leaving the crystalline portion of the polymer susceptible to hydrolytic attack. Upon collapse of the crystalline regions the polymer chain dissolves.
When exposed to physiological conditions, polyglycolide is degraded by random hydrolysis and apparently it is also broken down by certain enzymes, especially those with esterase activity. The degradation product, glycolic acid, is non toxic and it can enter the tricarboxylic acid cycle after which it is excreted as water and carbon dioxide. A part of the glycolic acid is also excreted by urine
Studies undergone using polyglycolide-made sutures have shown that the material loses half of its strength after two weeks and 100% after four weeks. The polymer is completely resorbed by the organism in a time frame of four to six months.
Uses:
While known since 1954, PGA had found little use because of its ease of degradation when compared with other synthetic polymers. However in 1962 this polymer was used to develop the first synthetic absorbable suture which was marketed under the tradename of Dexon by the Davis & Geck subsidiary of the American Cyanamid Corporation. It is sold today as Surgicryl.
PGA suture is classified as a synthetic, absorbable, braided multifilament. It is coated with N-laurin and L-lysine, which render the thread extremely smooth, soft and safe for knotting. It is also coated with magnesium stearate and finally sterilized with ethylene oxide gas. It is naturally degraded in the body by hydrolysis and is absorbed as water-soluble monomers, completed between 60 and 90 days. Elderly, anemic and malnourished patients may absorb the suture more quickly. Its color is either violet or undyed and it is sold in sizes USP 6-0 (1 metric) to USP 2 (5 metric). It has the advantages of high initial tensile strength, smooth passage through tissue, easy handling, excellent knotting ability, and secure knot tying. It is commonly used for subcutaneous sutures, intracutaneous closures, abdominal and thoracic surgeries.
The traditional role of PGA as a biodegradable suture material has led to its evaluation in other biomedical fields. Implantable medical devices have been produced with PGA, including anastomosis rings, pins, rods, plates and screws. It has also been explored for tissue engineering or controlled drug delivery. Tissue engineering scaffolds made with polyglycolide have been produced following different approaches, but generally most of these are obtained through textile technologies in the form of non-woven meshes.
Poly(lactic acid) or polylactide (PLA) is a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the United States) or sugarcanes (in the rest of world). Although PLA has been known for more than a century, it has only been of commercial interest in recent years, in light of its biodegradability. The name "polylactic acid" is to be used with caution, not complying to standard nomenclatures (such as IUPAC) and potentially leading to ambiguity (PLA is not a polyacid (polyelectrolyte), but rather a polyester)
Synthesis:
Bacterial fermentation is used to produce lactic acid from corn starch or cane sugar. However, lactic acid cannot be directly polymerized to a useful product, because each polymerization reaction generates one molecule of water, the presence of which degrades the forming polymer chain to the point that only very low molecular weights are observed. Instead, lactic acid is oligomerized and then catalytically dimerized to make the cyclic lactide monomer. Although dimerization also generates water, it can be separated prior to polymerization. PLA of high molecular weight is produced from the lactide monomer by ring-opening polymerization using most commonly a stannous octane catalyst, but for laboratory demonstrations tin(II) chloride is often employed. This mechanism does not generate additional water, and hence, a wide range of molecular weights is accessible.
Polymerization of a racemic mixture of L- and D-lactides usually leads to the synthesis of poly-DL-lactide (PDLLA) which is amorphous. Use of stereospecific catalysts can lead to heterotactic PLA which has been found to show crystallinity. The degree of crystallinity, and hence many important properties, is largely controlled by the ratio of D to L enantiomers used, and to a lesser extent on the type of catalyst used.
Properties:
Due to the chiral nature of lactic acid, several distinct forms of polylactide exist: poly-L-lactide (PLLA) is the product resulting from polymerization of L,L-lactide (also known as L-lactide). PLLA has a crystallinity of around 37%, a glass transition temperature between 60-65 °C, a melting temperature between 173-178 °C and a tensile modulus between 2.7-16 GPa
PLA has similar mechanical properties to PTFE polymer, but has a significantly lower maximum continuous use temperature.
Polylactic acid can be processed like most thermoplastics into fiber (for example using conventional melt spinning processes) and film. The melting temperature of PLLA can be increased 40-50 °C and its heat deflection temperature can be increased from approximately 60°C to up to 190 °C by physically blending the polymer with PDLA (poly-D-lactide). PDLA and PLLA form a highly regular stereocomplex with increased crystallinity. The temperature stability is maximised when a 50:50 blend is used, but even at lower concentrations of 3-10% of PDLA, there is still a substantial improvement. In the latter case, PDLA acts as a nucleating agent, thereby increasing the crystallization rate. Biodegradation of PDLA is slower than for PLA due to the higher crystallinity of PDLA. PDLA has the useful property of being optically transparent.
Applications:
Stereocomplex blends of PDLA and PLLA have a wide range of applications, such as woven shirts (ironability), microwavable trays, hot-fill applications and even engineering plastics (in this case, the stereocomplex is blended with a rubber-like polymer such as ABS). Such blends also have good form-stability and visual transparency, making them useful for low-end packaging applications. Progress in biotechnology has resulted in the development of commercial production of the D enantiomer form, something that was not possible until recently.
PLA is currently used in a number of biomedical applications, such as sutures, stents, dialysis media and drug delivery devices. It is also being evaluated as a material for tissue engineering. Because it is biodegradable, it can also be employed in the preparation of bioplastic, useful for producing loose-fill packaging, compost bags, food packaging, and disposable tableware. In the form of fibers and non-woven textiles, PLA also has many potential uses, for example as upholstery, disposable garments, awnings, feminine hygiene products, and nappies.
PLA has been used as the hydrophobic block of amphiphilic synthetic block copolymers used to form the vesicle membrane of polymersomes.
PLA is a sustainable alternative to petrochemical-derived products, since the lactides from which it is ultimately produced can be derived from the fermentation of agricultural by-products such as corn starch or other carbohydrate-rich substances like maize, sugar or wheat.
PLA is more expensive than many petroleum-derived commodity plastics, but its price has been falling as production increases. The demand for corn is growing, both due to the use of corn for bioethanol and for corn-dependent commodities, including PLA.
PLA has also been developed in the United Kingdom to serve as sandwich packaging.
PLA has also been used in France to serve as the binder in Isonat Nat’isol, an hemp fiber building insulation.
PLA is used for biodegradable and compostable disposable cups for cold beverages, the lining in cups for hot beverages, deli containers and clamshells for food packaging.
2. CELLOPHANE
Cellophane is a thin, transparent sheet made of regenerated cellulose. Its low permeability to air, oils, greases, and bacteria makes it useful for food packaging. Cellophane is in many countries a registered trade mark of Innovia Films Ltd, Cumbria, UK
Production:
Cellulose from wood, cotton, hemp, or other sources is dissolved in alkali and carbon disulfide to make a solution called viscose, which is then extruded through a slit into a bath of dilute sulfuric acid and sodium sulfate to reconvert the viscose into cellulose. The film is then passed through several more baths, one to remove sulfur, one to bleach the film, and one to add glycerin to prevent the film from becoming brittle.
A similar process, using a hole (a spinneret) instead of a slit, is used to make a fibre called rayon. Chemically, cellophane, rayon and cellulose are polymers of glucose and contain the chemical elements carbon, hydrogen, and oxygen.
Polymerization
Applications:Cellulose film has been manufactured continuously since the mid-1930s and is still used today. As well as packaging a variety of food items, there are also industrial applications, such as a base for such self-adhesive tapes as Sellotape and Scotch Tape, a semi-permeable membrane in a certain type of battery, as dialysis tubing (Visking tubing) and as a release agent in the manufacture of fibreglass and rubber products. The word "cellophane" has become genericized in the US, and is often used informally to refer to a wide variety of plastic film products, even those not made of cellulose. However, in the UK and in many other countries it is still a registered trademark and the property of Innovia Films Ltd.
Cellophane sales have dwindled since the 1960s due to use of alternative packaging options, and the fact that viscose is becoming less common because of the polluting effects of carbon disulfide and other by-products of the process used to make it. However, the fact that cellophane is 100% biodegradable has increased its popularity as a food wrapping. Cellophane is the most popular material for manufacturing cigar packaging; its permeability to moisture makes cellophane the perfect product for this application as cigars must be allowed to "breathe" while in storage.
When placed between two plane polarizing filters, cellophane produces prismatic colors due to its birefringent nature. Artists have used this effect to create stained glass-like creations that are kinetic and interactive.
3. PLASTARCH MATERIAL
Plastarch Material (PSM) is a biodegradable, thermoplastic resin. It is composed of starch combined with several other biodegradable materials. The starch is modified in order to obtain heat-resistant properties, making PSM one of few bioplastics capable of withstanding high temperatures. PSM began to be commercially available in 2005.
PSM is stable in the atmosphere, but biodegradable in compost, wet soil, fresh water, seawater, and activated sludge where microorganisms exist. It has a softening temperature of 257°F (125°C) and a melting temperature of 313°F (156°C).
It is also hygroscopic. The material has to be dried in a material dryer at 150°F (66°C) for five hours or 180°F (82°C) for three hours. For injection molding and extrusion the barrel temperatures should be at 340° +/- 10°F (171°C) with the nozzle/die at 360°F (182°C).
Due to how similar PSM is to other plastics (such as polypropylene and CPET), PSM can run on many existing thermoforming and injection molding lines. PSM is currently used for a wide variety of applications in the plastic market, such as food packaging and utensils, personal care items, plastic bags, temporary construction tubing, industrial foam packaging, industrial and agricultural film, window insulation, construction stakes, and horticulture planters.
Since PSM is derived from a renewable resource (corn), it has become an attractive alternative to petrochemical-derived products. Unlike plastic, PSM can also be disposed of through incineration, resulting in non-toxic smoke and a white residue which can be used as fertilizer.
4.Polycaprolactone (PCL)
is a biodegradable polyester with a low melting point of around 60°C and a glass transition temperature of about −60°C. PCL is prepared by ring opening polymerization of ε-caprolactone using a catalyst such as stannous octanoate. The most common use of polycaprolactone is in the manufacture of speciality polyurethanes. Polycaprolactones impart good water, oil, solvent and chlorine resistance to the polyurethane produced.
This polymer is often used as an additive for resins to improve their processing characteristics and their end use properties (e.g., impact resistance). Being compatible with a range of other materials, PCL can be mixed with starch to lower its cost and increase biodegradability or it can be added as a polymeric plasticizer to PVC.
Polycaprolactone is also used for splinting, modeling, and as a feedstock for prototyping systems such as a RepRap, where it is used for Fused Filament Fabrication (similar to the Stratasys' Fused Deposition Modeling or FDM technique).
Biomedical applications:
PCL is degraded by hydrolysis of its ester linkages in physiological conditions (such as in the human body) and has therefore received a great deal of attention for use as an implantable biomaterial. In particular it is especially interesting for the preparation of long term implantable devices, owing to its degradation which is even slower than that of polylactide.
PCL is an Food and Drug Administration (FDA) approved material that is used in the human body as (for example) a drug delivery device, suture (sold under the brand name Monocryl or generically), or adhesion barrier. It is being investigated as a scaffold for tissue repair via tissue engineering, GBR membrane. It has been used as the hydrophobic block of amphiphilic synthetic block copolymers used to form the vesicle membrane of polymersomes.
A variety of drugs have been encapsulated within PCL beads for controlled release and targeted drug delivery which have been peer reviewed
The major impurities in the medical grade are toluene (<890 ppm, usually about 100 ppm) and tin (<200ppm).
In odontology or dentistry (as composite named Resilon), it is used in root canal filling. It performs like gutta-percha, has the same handling properties, and for retreatment purposes may be softened with heat, or dissolved with solvents like chloroform. Similar to gutta-percha, there are master cones in all ISO sizes and accessory cones in different sizes available. The major difference between the polycaprolactone-based root canal filling material (Resilon and Real Seal) and gutta-percha is that the PCL-based material is biodegradable but the gutta-percha is not. There is lack of consensus in the expert dental community as to whether a resorbable root canal filling material, such as Resilon or Real Seal is desirable.
Hobbyist and Prototyping:
PCL also has many applications in the hobbyist market. Some brand names used in selling it to this market are Shapelock and Friendly Plastic in the US, and Polymorph in the UK. It has physical properties of a very tough, nylon-like plastic that melts to a putty-like consistency at only 60°C. PCL's specific heat and conductivity are low enough that it is not hard to handle at this temperature.
5. Polyglycolide or Polyglycolic acid (PGA):
is a biodegradable, thermoplastic polymer and the simplest linear, aliphatic polyester. It can be prepared starting from glycolic acid by means of polycondensation or ring-opening polymerization. PGA has been known since 1954 as a tough fiber-forming polymer. Owing to its hydrolytic instability, however, its use has initially been limited. Currently polyglycolide and its copolymers (poly(lactic-co-glycolic acid) with lactic acid, poly(glycolide-co-caprolactone) with ε-caprolactone, and poly (glycolide-co-trimethylene carbonate) with trimethylene carbonate) are widely used as a material for the synthesis of absorbable sutures and are being evaluated in the biomedical field
Synthesis:
Polyglycolide can be obtained through several different processes starting with different materials:
1. polycondensation of glycolic acid;
2. ring-opening polymerization of glycolide;
3. solid-state polycondensation of halogenoacetates;
4. acid catalyzed reaction of carbon monoxide and formaldehyde
Polycondensation of glycolic acid is the simplest process available to prepare PGA, but it is not the most efficient because it yields a low molecular weight product. Briefly, the procedure is as follows: glycolic acid is heated at atmospheric pressure and a temperature of about 175-185°C is maintained until water ceases to distill. Subsequently, pressure is reduced to 150 mm Hg, still keeping the temperature unaltered for about two hours and the low MW polyglycolide is obtained.
The most common synthesis used to produce a high molecular weight form of the polymer is ring-opening polymerization of "glycolide", the cyclic diester of glycolic acid. Glycolide can be prepared by heating under reduced pressure low MW PGA, collecting the diester by means of distillation. Ring-opening polymerization of glycolide can be catalyzed using different catalysts, including antimony compounds, such as antimony trioxide or antimony trihalides, zinc compounds (zinc lactate) and tin compounds like stannous octoate (tin(II) 2-ethylhexanoate) or tin alkoxides. Stannous octoate is the most commonly used initiator, since it is approved by the FDA as a food stabilizer. Usage of other catalysts has been disclosed as well, among these are aluminum isopropoxide, calcium acetylacetonate, and several lanthanide alkoxides (e.g. yttrium isopropoxide).The procedure followed for ring-opening polymerization is briefly outlined: a catalytic amount of initiator is added to glycolide under a nitrogen atmosphere at a temperature of 195°C. The reaction is allowed to proceed for about two hours, then temperature is raised to 230°C for about half an hour. After solidification the resulting high MW polymer is collected
Another procedure consists in the thermally induced solid-state polycondensation of halogenoacetates with general formula X-—CH2COO-M+ (where M is a monovalent metal like sodium and X is a halogen like chlorine), resulting in the production of polyglycolide and small crystals of a salt. Polycondensation is carried out by heating an halogenoacetate, like sodium chloroacetate, at a temperature between 160-180°C, continuously passing nitrogen through the reaction vessel. During the reaction polyglycolide is formed along with sodium chloride which precipitates within the polymeric matrix; the salt can be conveniently removed by washing the product of the reaction with water.
PGA can also be obtained by reacting carbon monoxide, formaldehyde or one of its related compounds like paraformaldehyde or trioxane, in presence of an acidic catalyst. In a carbon monoxide atmosphere an autoclave is loaded with the catalyst (chlorosulfonic acid), dichloromethane and trioxane, then it is charged with carbon monoxide until aspecific pressure is reached; the reaction is stirred and allowed to proceed at a temperature of about 180°C for two hours. Upon completion the unreacted carbon monoxide is discharged and a mixture of low and high MW polyglycolide is collected
Physical properties:
Polyglycolide has a glass transition temperature between 35-40 °C and its melting point is reported to be in the range of 225-230 °C. PGA also exhibits an elevated degree of crystallinity, around 45-55%, thus resulting in insolubility in water. The solubility of this polyester is somewhat unique, in that its high molecular weight form is insoluble in almost all common organic solvents (acetone, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran), while low molecular weight oligomers sufficiently differ in their physical properties to be more soluble. However, polyglycolide is soluble in highly fluorinated solvents like hexafluoroisopropanol (HFIP) and hexafluoroacetone sesquihydrate, that can be used to prepare solutions of the high MW polymer for melt spinning and film preparation. Fibers of PGA exhibit high strength and modulus (7 GPa) and are particularly stiff.
Degradation:
Polyglycolide is characterized by hydrolytic instability owing to the presence of the ester linkage in its backbone. The degradation process is erosive and appears to take place in two steps during which the polymer is converted back to its monomer glycolic acid: first water diffuses into the amorphous (non-crystalline) regions of the polymer matrix, cleaving the ester bonds; the second step starts after the amorphous regions have been eroded, leaving the crystalline portion of the polymer susceptible to hydrolytic attack. Upon collapse of the crystalline regions the polymer chain dissolves.
When exposed to physiological conditions, polyglycolide is degraded by random hydrolysis and apparently it is also broken down by certain enzymes, especially those with esterase activity. The degradation product, glycolic acid, is non toxic and it can enter the tricarboxylic acid cycle after which it is excreted as water and carbon dioxide. A part of the glycolic acid is also excreted by urine
Studies undergone using polyglycolide-made sutures have shown that the material loses half of its strength after two weeks and 100% after four weeks. The polymer is completely resorbed by the organism in a time frame of four to six months.
Uses:
While known since 1954, PGA had found little use because of its ease of degradation when compared with other synthetic polymers. However in 1962 this polymer was used to develop the first synthetic absorbable suture which was marketed under the tradename of Dexon by the Davis & Geck subsidiary of the American Cyanamid Corporation. It is sold today as Surgicryl.
PGA suture is classified as a synthetic, absorbable, braided multifilament. It is coated with N-laurin and L-lysine, which render the thread extremely smooth, soft and safe for knotting. It is also coated with magnesium stearate and finally sterilized with ethylene oxide gas. It is naturally degraded in the body by hydrolysis and is absorbed as water-soluble monomers, completed between 60 and 90 days. Elderly, anemic and malnourished patients may absorb the suture more quickly. Its color is either violet or undyed and it is sold in sizes USP 6-0 (1 metric) to USP 2 (5 metric). It has the advantages of high initial tensile strength, smooth passage through tissue, easy handling, excellent knotting ability, and secure knot tying. It is commonly used for subcutaneous sutures, intracutaneous closures, abdominal and thoracic surgeries.
The traditional role of PGA as a biodegradable suture material has led to its evaluation in other biomedical fields. Implantable medical devices have been produced with PGA, including anastomosis rings, pins, rods, plates and screws. It has also been explored for tissue engineering or controlled drug delivery. Tissue engineering scaffolds made with polyglycolide have been produced following different approaches, but generally most of these are obtained through textile technologies in the form of non-woven meshes.
Wednesday, September 15, 2010
Packaging Industry in India
Second-tier cities become centre of packaging activity
The rise in organised retailing in India’s second-tier cities made for a competitive packaging market in 2008. Companies like Hindustan Unilever Ltd, Procter & Gamble India Ltd, Nestlé India Ltd, ITC Ltd, Coca-Cola India Ltd, PepsiCo India Ltd and Dabur India Ltd became very aggressive during the review period, and packaging became a big tool for launching new, India-specific products in different shapes and sizes. The review period witnessed a flux of partnerships and joint ventures, with many foreign packaging players entering the scene to gain a slice of the large pie. Alcan Packaging- part of Rio Tinto Alcan, Klockner Pentaplast Group (KP) - a German-based packaging solutions provider, Polish firm Can Pak and Bosch Packaging either announced new investments or disclosed plans for the expansion of their existing investments during the review period.
Environmental concerns continue to hamper polymer-based packaging growth
Environmental concerns are fast catching the attention of all the stake holders in the Indian packaging industry. The expansion of packaging as a profitable industry in India, dragged along by that of the retail and FMCG sectors, has brought with it environmental concerns. Organizations such as the Indian Centre for Plastics in the Environment were actively seen promoting awareness in this regard in order to promote the packaging industry and make people aware of the real concerns about the environment. The centre is the accredited body of The Ministry of Environment and Forests (MOEF) and undertook continuous awareness programs by publishing information on waste management materials, statistics, as well as going in to school and colleges and teaching people about the correct usage of polymer. Corporations were also seen to be making efforts to adapt greener technologies.
Cost advantages make India a preferred packaging export hub
Due to lower manufacturing costs, India is fast becoming a preferred hub for packaging production. The Indian packaging industry has made a mark with its exports that comprise flattened cans, printed sheets and components, crown cork, lug caps, plastic film laminates, craft paper, paper board and packaging machinery, while the imports include tinplate, lacquers, coating and lining compounds. In India, the fastest growing packaging segments are laminates and flexible packaging, especially PET and woven sacks. On the global scene ruled by the World Trade Organisation, it is imperative for India to upgrade its packaging standards through innovative technologies in order to be on a par with the world’s best practice. Packaging labels must inform consumers about the ingredients of the product, the nutritional value, and the manufacturing and expiry dates of the products; something which is being made mandatory by the government. Almost all the major players were seen to expand their existing capabilities to tap into the fast growing export market for Indian packaging products.
The rise in organised retailing in India’s second-tier cities made for a competitive packaging market in 2008. Companies like Hindustan Unilever Ltd, Procter & Gamble India Ltd, Nestlé India Ltd, ITC Ltd, Coca-Cola India Ltd, PepsiCo India Ltd and Dabur India Ltd became very aggressive during the review period, and packaging became a big tool for launching new, India-specific products in different shapes and sizes. The review period witnessed a flux of partnerships and joint ventures, with many foreign packaging players entering the scene to gain a slice of the large pie. Alcan Packaging- part of Rio Tinto Alcan, Klockner Pentaplast Group (KP) - a German-based packaging solutions provider, Polish firm Can Pak and Bosch Packaging either announced new investments or disclosed plans for the expansion of their existing investments during the review period.
Environmental concerns continue to hamper polymer-based packaging growth
Environmental concerns are fast catching the attention of all the stake holders in the Indian packaging industry. The expansion of packaging as a profitable industry in India, dragged along by that of the retail and FMCG sectors, has brought with it environmental concerns. Organizations such as the Indian Centre for Plastics in the Environment were actively seen promoting awareness in this regard in order to promote the packaging industry and make people aware of the real concerns about the environment. The centre is the accredited body of The Ministry of Environment and Forests (MOEF) and undertook continuous awareness programs by publishing information on waste management materials, statistics, as well as going in to school and colleges and teaching people about the correct usage of polymer. Corporations were also seen to be making efforts to adapt greener technologies.
Cost advantages make India a preferred packaging export hub
Due to lower manufacturing costs, India is fast becoming a preferred hub for packaging production. The Indian packaging industry has made a mark with its exports that comprise flattened cans, printed sheets and components, crown cork, lug caps, plastic film laminates, craft paper, paper board and packaging machinery, while the imports include tinplate, lacquers, coating and lining compounds. In India, the fastest growing packaging segments are laminates and flexible packaging, especially PET and woven sacks. On the global scene ruled by the World Trade Organisation, it is imperative for India to upgrade its packaging standards through innovative technologies in order to be on a par with the world’s best practice. Packaging labels must inform consumers about the ingredients of the product, the nutritional value, and the manufacturing and expiry dates of the products; something which is being made mandatory by the government. Almost all the major players were seen to expand their existing capabilities to tap into the fast growing export market for Indian packaging products.
STEADY INCREASE IN UK RECYCLING RATE
The recycling rate for plastics bottles in the UK has increased by 9 per cent from 2009, reaching 45 per cent this year, according to Recoup, a British charity for the development of plastics recycling.
The information was gathered from waste collection authorities and unitary authorities as part of the 2010 UK Household Plastics Packaging Collection Survey, and found that 84 local authorities are actively collecting non-bottle plastics for recycling (mixed plastics), with more than 40,000 tonnes collected in 2009.
More than 260,000 tonnes of plastics bottles were collected in 2009, with a high increase in material collected through kerbside systems, to more than 215,000 tonnes.
A detailed report will be available in October on the Recoup website: http://www.recoup.org/
What about India ?? wait for my next article.
The information was gathered from waste collection authorities and unitary authorities as part of the 2010 UK Household Plastics Packaging Collection Survey, and found that 84 local authorities are actively collecting non-bottle plastics for recycling (mixed plastics), with more than 40,000 tonnes collected in 2009.
More than 260,000 tonnes of plastics bottles were collected in 2009, with a high increase in material collected through kerbside systems, to more than 215,000 tonnes.
A detailed report will be available in October on the Recoup website: http://www.recoup.org/
What about India ?? wait for my next article.
Are Plastic Grocery Bags Sacking the Environment?
The "paper or plastic" conundrum that vexed earnest shoppers throughout the 1980s and 90s is largely moot today. Most grocery store baggers don't bother to ask anymore. They drop the bananas in one plastic bag as they reach for another to hold the six-pack of soda. The pasta sauce and noodles will get one too, as will the dish soap.
Plastic bags are so cheap to produce, sturdy, plentiful, easy to carry and store that they have captured at least 80 percent of the grocery and convenience store market since they were introduced a quarter century ago, according to the Plastics Council.
As a result, the totes are everywhere. They sit balled up and stuffed into the one that hangs from the pantry door. They line bathroom trash bins. They carry clothes to the gym. They clutter landfills. They flap from trees. They float in the breeze. They clog roadside drains. They drift on the high seas. They fill sea turtle bellies.
"The numbers are absolutely staggering," said Vincent Cobb, an entrepreneur in Chicago, Illinois, who recently launched the Web site http://Reusablebags.com to educate the public about what he terms the "true costs" associated with the spread of "free" bags. He sells reusable bags as a viable solution.
According to Cobb's calculations extrapolated from data released by the United States Environmental Protection Agency in 2001 on U.S. plastic bag, sack, and wrap consumption, somewhere between 500 billion and a trillion plastic bags are consumed worldwide each year. Of those, millions end up in the litter stream outside of landfills—estimates range from less than one to three percent of the bags.
Laurie Kusek, a spokeswoman for the American Plastics Council, said the industry works with its U.S. retail customers to encourage recycling of plastic bags, which are in high demand from companies such as Trex in Winchester, Virginia, for use in building materials.
"We also feel it is important to understand that plastic grocery bags are some of the most reused items around the house," she said. "Many, many bags are reused as book and lunch bags as kids head off to school, as trash can liners, and to pickup Fido's droppings off the lawn."
But like candy wrappers, chewing gum, cigarette butts, and thousands of other pieces of junk, millions of the plastic bags end up as litter. Once in the environment, it takes months to hundreds of years for plastic bags to breakdown. As they decompose, tiny toxic bits seep into soils, lakes, rivers, and the oceans, said Cobb.
Plastic Fantastic
The Film and Bag Federation, a trade group within the Society of the Plastics Industry based in Washington, D.C., said the right choice between paper or plastic bags is clearly plastic.
Compared to paper grocery bags, plastic grocery bags consume 40 percent less energy, generate 80 percent less solid waste, produce 70 percent fewer atmospheric emissions, and release up to 94 percent fewer waterborne wastes, according to the federation.
Robert Bateman, president of Roplast Industries, a manufacturer of plastic bags—including reusable ones—in Oroville, California, said the economic advantage of plastic bags over paper bags has become too significant for store owners to ignore. It costs one cent for a standard plastic grocery sack, whereas a paper bag costs four cents, he said.
"The plastic bags are so inexpensive that in the stores no one treats them as worth anything … they use two, three, or four when one would do just as well," he said.
First introduced in the 1970s, plastic bags now account for four out of every five bags handed out at the grocery store. "When you look at it as a product, it is an unbelievable success story," said Cobb.
The success of the plastic bag has meant a dramatic increase in the amount of sacks found floating in the oceans where they choke, strangle, and starve wildlife and raft alien species around the world, according to David Barnes, a marine scientist with the British Antarctic Survey in Cambridge, England, who studies the impact of marine debris.
Barnes said that plastic bags have gone "from being rare in the late 80s and early 90s to being almost everywhere from Spitsbergen 78° North [latitude] to Falklands 51° South [latitude], but I'll bet they'll be washing up in Antarctica within the decade."
Bateman said that plastic bags are becoming a victim of their success. "The industry is at the stage where its success has caused concerns and these concerns need to be addressed responsibly," he said. Among other initiatives, Bateman supports the development of biodegradable plastic bags, a technology that has made strides in recent years.
Plastax to the Rescue?
Plastic bag litter has become such an environmental nuisance and eyesore that Ireland, Taiwan, South Africa, Australia, and Bangladesh have heavily taxed the totes or banned their use outright. Several other regions, including England and some U.S. cities, are considering similar actions.
Tony Lowes, director of Friends of the Irish Environment in County Cork, said the 15 cent (about 20 cents U.S.) tax on plastic bags introduced there in March 2002 has resulted in a 95 percent reduction in their use. "It's been an extraordinary success," he said.
According to Lowes, just about everyone in Ireland carries around a reusable bag and the plastic bags that once blighted the verdant Irish countryside are now merely an occasional eyesore. Cobb believes a similar tax in the U.S. would have a similar effect on reducing consumption.
The American Plastics Council is wary of such a tax in the U.S. They say it would cost tens of thousands of jobs and result in an increase in energy consumption, pollution, landfill space, and grocery prices as store owners increase reliance on more expensive paper bags as an alternative.
Bateman said the Irish tax of about U.S. 20 cents per bag is too high, but that a tax of 3 to 5 cents could have a positive impact on reducing plastic bag consumption by changing people's behavior.
"Having bags charged has some merits because it gets them used more responsibly," he said. For example, instead of a bagger using six bags to package a person's dinner, the bagger might use just two.
As for Cobb, he hopes people will begin to realize that paper and plastic bags both come at great cost to the environment and instead of scratching their head when asked which type they prefer, they'll pull a tightly packed reusable bag from their pocket.
"We want to make it cool to carry reusable shopping bags," he said.
courtesy:John Roach
National Geographic News
Plastic bags are so cheap to produce, sturdy, plentiful, easy to carry and store that they have captured at least 80 percent of the grocery and convenience store market since they were introduced a quarter century ago, according to the Plastics Council.
As a result, the totes are everywhere. They sit balled up and stuffed into the one that hangs from the pantry door. They line bathroom trash bins. They carry clothes to the gym. They clutter landfills. They flap from trees. They float in the breeze. They clog roadside drains. They drift on the high seas. They fill sea turtle bellies.
"The numbers are absolutely staggering," said Vincent Cobb, an entrepreneur in Chicago, Illinois, who recently launched the Web site http://Reusablebags.com to educate the public about what he terms the "true costs" associated with the spread of "free" bags. He sells reusable bags as a viable solution.
According to Cobb's calculations extrapolated from data released by the United States Environmental Protection Agency in 2001 on U.S. plastic bag, sack, and wrap consumption, somewhere between 500 billion and a trillion plastic bags are consumed worldwide each year. Of those, millions end up in the litter stream outside of landfills—estimates range from less than one to three percent of the bags.
Laurie Kusek, a spokeswoman for the American Plastics Council, said the industry works with its U.S. retail customers to encourage recycling of plastic bags, which are in high demand from companies such as Trex in Winchester, Virginia, for use in building materials.
"We also feel it is important to understand that plastic grocery bags are some of the most reused items around the house," she said. "Many, many bags are reused as book and lunch bags as kids head off to school, as trash can liners, and to pickup Fido's droppings off the lawn."
But like candy wrappers, chewing gum, cigarette butts, and thousands of other pieces of junk, millions of the plastic bags end up as litter. Once in the environment, it takes months to hundreds of years for plastic bags to breakdown. As they decompose, tiny toxic bits seep into soils, lakes, rivers, and the oceans, said Cobb.
Plastic Fantastic
The Film and Bag Federation, a trade group within the Society of the Plastics Industry based in Washington, D.C., said the right choice between paper or plastic bags is clearly plastic.
Compared to paper grocery bags, plastic grocery bags consume 40 percent less energy, generate 80 percent less solid waste, produce 70 percent fewer atmospheric emissions, and release up to 94 percent fewer waterborne wastes, according to the federation.
Robert Bateman, president of Roplast Industries, a manufacturer of plastic bags—including reusable ones—in Oroville, California, said the economic advantage of plastic bags over paper bags has become too significant for store owners to ignore. It costs one cent for a standard plastic grocery sack, whereas a paper bag costs four cents, he said.
"The plastic bags are so inexpensive that in the stores no one treats them as worth anything … they use two, three, or four when one would do just as well," he said.
First introduced in the 1970s, plastic bags now account for four out of every five bags handed out at the grocery store. "When you look at it as a product, it is an unbelievable success story," said Cobb.
The success of the plastic bag has meant a dramatic increase in the amount of sacks found floating in the oceans where they choke, strangle, and starve wildlife and raft alien species around the world, according to David Barnes, a marine scientist with the British Antarctic Survey in Cambridge, England, who studies the impact of marine debris.
Barnes said that plastic bags have gone "from being rare in the late 80s and early 90s to being almost everywhere from Spitsbergen 78° North [latitude] to Falklands 51° South [latitude], but I'll bet they'll be washing up in Antarctica within the decade."
Bateman said that plastic bags are becoming a victim of their success. "The industry is at the stage where its success has caused concerns and these concerns need to be addressed responsibly," he said. Among other initiatives, Bateman supports the development of biodegradable plastic bags, a technology that has made strides in recent years.
Plastax to the Rescue?
Plastic bag litter has become such an environmental nuisance and eyesore that Ireland, Taiwan, South Africa, Australia, and Bangladesh have heavily taxed the totes or banned their use outright. Several other regions, including England and some U.S. cities, are considering similar actions.
Tony Lowes, director of Friends of the Irish Environment in County Cork, said the 15 cent (about 20 cents U.S.) tax on plastic bags introduced there in March 2002 has resulted in a 95 percent reduction in their use. "It's been an extraordinary success," he said.
According to Lowes, just about everyone in Ireland carries around a reusable bag and the plastic bags that once blighted the verdant Irish countryside are now merely an occasional eyesore. Cobb believes a similar tax in the U.S. would have a similar effect on reducing consumption.
The American Plastics Council is wary of such a tax in the U.S. They say it would cost tens of thousands of jobs and result in an increase in energy consumption, pollution, landfill space, and grocery prices as store owners increase reliance on more expensive paper bags as an alternative.
Bateman said the Irish tax of about U.S. 20 cents per bag is too high, but that a tax of 3 to 5 cents could have a positive impact on reducing plastic bag consumption by changing people's behavior.
"Having bags charged has some merits because it gets them used more responsibly," he said. For example, instead of a bagger using six bags to package a person's dinner, the bagger might use just two.
As for Cobb, he hopes people will begin to realize that paper and plastic bags both come at great cost to the environment and instead of scratching their head when asked which type they prefer, they'll pull a tightly packed reusable bag from their pocket.
"We want to make it cool to carry reusable shopping bags," he said.
courtesy:John Roach
National Geographic News
Sunday, September 12, 2010
Plastics and the Environment - Villain or Friend?
Plastic is often labeled a villain by environmental activists. Because it is used in packaging and single-use products, plastic seems to symbolize our "throw-away" culture. Plastic products also are criticized because they do not biodegrade and because they are manufactured from nonrenewable resources. That popular view of plastic overlooks plastic's true place in the environment. How should people concerned with protecting the environment think about plastic?
Environmental Benefits
Plastic has features that benefit the environment. For example, plastic reduces food waste by about 1.7 pounds for every pound of packaging. Plastic allows us to store food and leftovers for longer periods of time. And because it can be transparent, plastic packaging allows us to check for spoilage or damage before we buy or use a product.
Plastic conserves energy by requiring less energy to make than other forms of packaging. And because it is light and less bulky, plastic reduces the amount of fuel used by trucks and vans that transport goods from factories and dairies to stores.
Plastic packaging often produces less pollution during its manufacturing process than the forms of packaging it replaces. Compared to a paper cup, for example, manufacturing a plastic foam cup produces much less air and water pollution.
This doesn't mean plastic is always better than other types of packaging. But oftentimes, plastic is better for the environment than other types of packaging. Campaigning against everything made of plastic doesn't help the environment, and it surely doesn't help consumers.
Running Out of Room?
Some people think plastic packaging is causing us to run out of room to put our solid waste. But plastic packaging amounts to a very small fraction of municipal waste - less than 5 percent by weight, according to the Environmental Protection Agency. Plastic food and drink containers, often singled out for attack by environmentalists, amount to less than 0.5 percent of all municipal solid waste, less than phone books alone. Old clothes and shoes equal 11 times as much!
Natural Resources
Plastic is made from petroleum or natural gas, but using plastic packaging isn't likely to cause us to run out of oil or gas. The production of plastic accounts for less than 3 percent of the oil and gas consumed each year. And the world's oil and gas reserves keep growing as new parts of the world are explored. For example, known reserves of oil and gas rose by nearly a factor of 10 during the past 40 years - from 30 to 250 million metric tons. One expert estimates that total fossil fuel resources could last 650 years at current rates of consumption.
Biodegradable
Most plastics do not biodegrade, but in a modern landfill, neither does most of the paper and other kinds of packaging. Modern landfills are nearly airtight and have sophisticated systems to prevent moisture from entering or collecting in the waste. Consequently, paper and even organic waste (like discarded food) are preserved or biodegrade very slowly inside a modern landfill. New landfill technologies mean a material's ability to biodegrade is less important than how much room it occupies. Since plastic packaging is often thinner and lighter than other kinds of packaging it has an advantage over heavier but biodegradable materials.
Recycling
It is a myth that plastic can't be recycled. In fact, 49 percent of plastic soft drink bottles are being recycled, which is about the same as the recycling rate for glass bottles and steel cans, whose recycling programs have been around for much longer. Additionally, thousands of products are being produced from recycled plastics each year. These products include clothing, office supplies, construction materials, and packaging.
Conclusion
An honest evaluation suggests that plastic is not the villain some people say it is. The truth is that plastic plays only a small role in the nation's solid waste problem, and many of plastic's features actually benefit the environment.
We should not assume that a plastic package is less "environmentally correct" than a paper, glass, aluminum, or steel package. Each kind of package has advantages and disadvantages, and some are better for some uses than others. This balanced view will help both consumers and the environment.
Environmental Benefits
Plastic has features that benefit the environment. For example, plastic reduces food waste by about 1.7 pounds for every pound of packaging. Plastic allows us to store food and leftovers for longer periods of time. And because it can be transparent, plastic packaging allows us to check for spoilage or damage before we buy or use a product.
Plastic conserves energy by requiring less energy to make than other forms of packaging. And because it is light and less bulky, plastic reduces the amount of fuel used by trucks and vans that transport goods from factories and dairies to stores.
Plastic packaging often produces less pollution during its manufacturing process than the forms of packaging it replaces. Compared to a paper cup, for example, manufacturing a plastic foam cup produces much less air and water pollution.
This doesn't mean plastic is always better than other types of packaging. But oftentimes, plastic is better for the environment than other types of packaging. Campaigning against everything made of plastic doesn't help the environment, and it surely doesn't help consumers.
Running Out of Room?
Some people think plastic packaging is causing us to run out of room to put our solid waste. But plastic packaging amounts to a very small fraction of municipal waste - less than 5 percent by weight, according to the Environmental Protection Agency. Plastic food and drink containers, often singled out for attack by environmentalists, amount to less than 0.5 percent of all municipal solid waste, less than phone books alone. Old clothes and shoes equal 11 times as much!
Natural Resources
Plastic is made from petroleum or natural gas, but using plastic packaging isn't likely to cause us to run out of oil or gas. The production of plastic accounts for less than 3 percent of the oil and gas consumed each year. And the world's oil and gas reserves keep growing as new parts of the world are explored. For example, known reserves of oil and gas rose by nearly a factor of 10 during the past 40 years - from 30 to 250 million metric tons. One expert estimates that total fossil fuel resources could last 650 years at current rates of consumption.
Biodegradable
Most plastics do not biodegrade, but in a modern landfill, neither does most of the paper and other kinds of packaging. Modern landfills are nearly airtight and have sophisticated systems to prevent moisture from entering or collecting in the waste. Consequently, paper and even organic waste (like discarded food) are preserved or biodegrade very slowly inside a modern landfill. New landfill technologies mean a material's ability to biodegrade is less important than how much room it occupies. Since plastic packaging is often thinner and lighter than other kinds of packaging it has an advantage over heavier but biodegradable materials.
Recycling
It is a myth that plastic can't be recycled. In fact, 49 percent of plastic soft drink bottles are being recycled, which is about the same as the recycling rate for glass bottles and steel cans, whose recycling programs have been around for much longer. Additionally, thousands of products are being produced from recycled plastics each year. These products include clothing, office supplies, construction materials, and packaging.
Conclusion
An honest evaluation suggests that plastic is not the villain some people say it is. The truth is that plastic plays only a small role in the nation's solid waste problem, and many of plastic's features actually benefit the environment.
We should not assume that a plastic package is less "environmentally correct" than a paper, glass, aluminum, or steel package. Each kind of package has advantages and disadvantages, and some are better for some uses than others. This balanced view will help both consumers and the environment.
Major Myths About Garbage, and Why They're Wrong
As part of the Garbage Project, established at the University of Arizona in 1973 to apply archaeological principles to a modern society, some 750 people processed more than 250,000 pounds of garbage during a five-year period. The garbage - 14 tons from nine municipal landfills in the U.S. and the balance taken from garbage trucks or at curbside - was sorted, weighed and catalogued to produce a database. The project uncovered a major problem: much conventional wisdom about garbage and its disposal consists of myths and assertions that turn out, upon investigation, to be misleading - or dead wrong.
Myth No. 1: Fast-food packaging, polystyrene foam and disposable diapers are major constituents of American garbage.
Findings: Of the 14 tons of landfilled garbage examined, fast-food packaging constituted less than 100 pounds (less than one-half of one percent by weight) of the excavated material. The Garbage Project estimates that this category of waste accounts for no more than one-third of 1 percent of the total volume of the average American landfill's contents; polystyrene foam, no more than 1 percent; and disposable diapers, 1.4 percent (1 percent by weight).
Myth No. 2: Plastic is also a big problem.
Findings: The authors note that although "plastic is the Great Satan of garbage, gaudy, cheap, a convenient scapegoat," paper was the largest component of the excavated landfills' contents, at 40 percent. Newspapers alone accounted for up to 13 percent. This proportion, they indicate, has held steady for decades or risen in some landfills.
Plastics, on the other hand, amounted to 20-24 percent (by volume) of all landfill garbage as sorted, or about 16 percent when compacted as under typical landfill conditions. The article notes that although the number of objects made from plastics has been increasing, the industry practice of "light-weighting" has substantially reduced the amount of material used in soda bottles, milk jugs, disposable diapers and other products. "...when plastic gets lighter, it also gets thinner and more crushable. The result is that more plastic items can be squeezed into a given volume of landfill space today than could fit 10 or 20 years ago."
Myth No. 3: A lot of biodegradation takes place in modern landfills.
Findings: The authors observe that people often defend paper because it biodegrades in landfills, while plastics take up space "until the end of time." Their findings indicate, however, that "biologically and chemically, a landfill is much more static than we commonly suppose. For some kinds of organic garbage, biodegradation goes on for a while and then slows to a virtual standstill. For other kinds, biodegradation never gets under way at all."
Most organic material excavated remained identifiable, including whole hot dogs, carrot tips and onionparings several decades old, and New Deal-era newspapers. "Under normal landfill conditions, in which...the landfill is kept relatively dry, the only types of garbage that truly decompose are certain kinds of food and yard waste." The authors conclude that "well-designed and well-managed landfills....are not vast composters; rather, they are vast mummifiers."
Myth No. 4: America is running out of safe places to put landfills.
Findings: The article cites a study in which A. Clark Wiseman, an economist at Resources for the Future, a Washington-based think tank, "calculated that at the current rate of waste generation, all of America's garbage for the next 1,000 years would fit into a single landfill space only 120 feet deep and 44 miles square" (three times the size of Oklahoma City). Citing additional studies, the authors observe, "Few nations are as substantially endowed with uncongested territory as ours is, and there is appropriate land available even in some relatively populous areas." The obstacles, as they see them, "are psychological and political. Nobody wants a garbage dump in his or her backyard. It is ironic. We have convinced ourselves that our big flaw is that we are wasteful and profligate, while a much more serious flaw goes unnoticed: as a nation, on the subject of garbage, at least, we have become politically impotent."
Myth No. 5: On a per-capita basis, Americans are producing garbage at a rapidly accelerating rate.
Findings: Garbage Project sortings of household garbage in Milwaukee revealed a disposal rate of 1.5 pounds per person per day, compared with the 1.9 pounds found in a study done in the city 20 years earlier, in 1959. According to the authors, the EPA estimates that the average American currently discards about 1,500 pounds of garbage annually. They note that at the turn of the century, we threw out coal ash alone at an average per-capita rate of 1,200 pounds per year. "It is undeniable that Americans as a whole are producing more municipal solid waste than they did 50 or 100 years ago. But this is largely because there are more Americans....A long view...would suggest that, on a per-capita basis, the nation's record is hardly one of unrestrained excess. Indeed, the word that best describes the situation with respect to overall volume may be 'stability'."
Conclusions
The authors conclude that while garbage disposal "requires serious attention,...the most critical part of the garbage problem in America may be that our notions about the creation and disposal of garbage are riddled with misconceptions. We go after symbolic targets rather than the serious but mundane ones. Impelled by a sense of crisis, we make hasty decisions when nothing about the situation warrants anything but calm. We castigate ourselves for certain imperfections but not for the ones that really matter. And we lose sight of fundamentals." These include the facts that our means of disposal "have never been safer or more technically advanced," and that our record with regard to garbage disposal has gradually improved since the late 19th century.
The solutions, as Rathje and Murphy see them, are:
•willingness on the part of consumers to pay pro-rated fees for collecting and disposing of nonrecyclable garbage;
•increased consumer-generated demand for goods and packaging with post-consumer recycled content above 10 percent; and
•alignment of the perception and the reality of our situation as a starting point for political discussion and decision making.
The 10-page Smithsonian article was adapted from the book Rubbish! The Archaeology of Garbage, written by William Rathje (head of the Garbage Project) and Cullen Murphy and published by Harper Collins.
Incineration of plastics
Q: What happens inside a modern waste-to-energy facility?
A: The energy value of municipal solid waste (MSW) can be recovered through waste-to-energy incineration. Modern energy recovery facilities burn MSW in special combustion chambers, then use the resulting heat energy to generate steam or electricity. This process reduces the volume of MSW to be landfilled by as much as 90 percent.
Energy recovery facilities are designed to achieve high combustion temperatures, which help MSW burn cleaner and create less ash for disposal. Modern air pollution control devices - electrostatic precipitators, dry and wet scrubbers, and/or fabric filters - are used to remove potentially harmful particulates and gases from incinerator emissions.
Q: Is waste-to-energy incineration safe?
A: Yes. In 1989, the U.S. Conference of Mayors convened an international blue-ribbon panel of experts to discuss the health and safety impacts of waste-to-energy incineration. The symposium participants concluded that a properly equipped, operated and maintained energy recovery facility can operate within existing regulatory standards for human health and safety. The Clean Air Act of 1991 provided for an additional margin of security with tightened emissions standards. Furthermore, many communities are recognizing the importance of removing recyclables, as well as items such as batteries and household hazardous wastes, before incineration to reduce toxic components in incinerator ash.
The symposium participants found that, contrary to popular misconception, there is no evidence to link the incineration of PVC with increased dioxin emissions. Similar conclusions have been reached in a number of sources, including a 1987 study for the New York State Energy Research and Development Authority. Generally speaking, electricity is generated as safely through waste-to-energy incineration as it is through a power plant.
Q: How much waste-to-energy capacity is there?
A: There are 121 energy recovery facilities operating in the United States, with a designed capacity of nearly 97,000 tons per day. An additional five facilities are under construction and 31 are in the planning stages. If all of these facilities come on line as planned, 19 percent of the nation's MSW will be processed by energy recovery facilities by the year 2000.
Q: How do plastics contribute to waste-to-energy incineration?
A: Plastics are derived from petroleum or natural gas, giving them a stored energy value higher than any other material commonly found in the waste stream. In fact, one pound of plastics can generate twice as much energy as Wyoming coal and almost as much energy as fuel oil. When plastics are processed in modern waste-to-energy facilities, they can help other waste combust more completely, leaving less ash for disposal in landfills.
Energy Values
Material Btu/pound
Plastics
PET 10,900
HDPE 18,700
Other Plastic Containers 16,400
Other Plastics 17,900
Rubber & Leather 12,800
Newspaper 8,000
Corrugated Boxes (paper) 7,000
Textiles 9,400
Wood 7,300
Average for MSW 5,900
Yard Wastes 2,900
Food Wastes 2,900
Heat Content of Common Fuels
Fuel Oil 20,900
Wyoming Coal 9,600
Courtesy: SPI
A: The energy value of municipal solid waste (MSW) can be recovered through waste-to-energy incineration. Modern energy recovery facilities burn MSW in special combustion chambers, then use the resulting heat energy to generate steam or electricity. This process reduces the volume of MSW to be landfilled by as much as 90 percent.
Energy recovery facilities are designed to achieve high combustion temperatures, which help MSW burn cleaner and create less ash for disposal. Modern air pollution control devices - electrostatic precipitators, dry and wet scrubbers, and/or fabric filters - are used to remove potentially harmful particulates and gases from incinerator emissions.
Q: Is waste-to-energy incineration safe?
A: Yes. In 1989, the U.S. Conference of Mayors convened an international blue-ribbon panel of experts to discuss the health and safety impacts of waste-to-energy incineration. The symposium participants concluded that a properly equipped, operated and maintained energy recovery facility can operate within existing regulatory standards for human health and safety. The Clean Air Act of 1991 provided for an additional margin of security with tightened emissions standards. Furthermore, many communities are recognizing the importance of removing recyclables, as well as items such as batteries and household hazardous wastes, before incineration to reduce toxic components in incinerator ash.
The symposium participants found that, contrary to popular misconception, there is no evidence to link the incineration of PVC with increased dioxin emissions. Similar conclusions have been reached in a number of sources, including a 1987 study for the New York State Energy Research and Development Authority. Generally speaking, electricity is generated as safely through waste-to-energy incineration as it is through a power plant.
Q: How much waste-to-energy capacity is there?
A: There are 121 energy recovery facilities operating in the United States, with a designed capacity of nearly 97,000 tons per day. An additional five facilities are under construction and 31 are in the planning stages. If all of these facilities come on line as planned, 19 percent of the nation's MSW will be processed by energy recovery facilities by the year 2000.
Q: How do plastics contribute to waste-to-energy incineration?
A: Plastics are derived from petroleum or natural gas, giving them a stored energy value higher than any other material commonly found in the waste stream. In fact, one pound of plastics can generate twice as much energy as Wyoming coal and almost as much energy as fuel oil. When plastics are processed in modern waste-to-energy facilities, they can help other waste combust more completely, leaving less ash for disposal in landfills.
Energy Values
Material Btu/pound
Plastics
PET 10,900
HDPE 18,700
Other Plastic Containers 16,400
Other Plastics 17,900
Rubber & Leather 12,800
Newspaper 8,000
Corrugated Boxes (paper) 7,000
Textiles 9,400
Wood 7,300
Average for MSW 5,900
Yard Wastes 2,900
Food Wastes 2,900
Heat Content of Common Fuels
Fuel Oil 20,900
Wyoming Coal 9,600
Courtesy: SPI
Plastics and Energy Efficiency !!
Q: Can plastics actually save energy?
A: Yes. And they use less energy than you might think: the raw materials that go into the production of plastics account for only 1.5 percent of total energy consumption. In addition, it often takes less energy to convert plastics from a raw material into a finished product than comparable products made of other materials:
• Plastic grocery bags require 40 percent less energy to make than paper bags.
• Foam polystyrene containers require 30 percent less total energy than paperboard containers.
• Fifty-three billion kilowatt hours of electricity are saved annually by improvement in major appliance energy efficiency made possible by plastic applications. Without plastics, these appliances would use 30 percent more energy.
Q: Would more energy be conserved if plastic packaging were replaced by non-plastic alternatives?
A: No. In fact, the total energy used in manufacturing plastic packaging is considerably less than the energy used to produce non-plastic alternatives -- even when the inherent energy value of plastics' raw materials is factored in. This means that without plastics, the equivalent of an additional 58 million barrels of oil or 325 billion cubic feet of natural gas would have been required to meet America's packaging needs in 1990. That's enough to meet the energy needs of 100,000 homes for 35 years.
A: Yes. And they use less energy than you might think: the raw materials that go into the production of plastics account for only 1.5 percent of total energy consumption. In addition, it often takes less energy to convert plastics from a raw material into a finished product than comparable products made of other materials:
• Plastic grocery bags require 40 percent less energy to make than paper bags.
• Foam polystyrene containers require 30 percent less total energy than paperboard containers.
• Fifty-three billion kilowatt hours of electricity are saved annually by improvement in major appliance energy efficiency made possible by plastic applications. Without plastics, these appliances would use 30 percent more energy.
Q: Would more energy be conserved if plastic packaging were replaced by non-plastic alternatives?
A: No. In fact, the total energy used in manufacturing plastic packaging is considerably less than the energy used to produce non-plastic alternatives -- even when the inherent energy value of plastics' raw materials is factored in. This means that without plastics, the equivalent of an additional 58 million barrels of oil or 325 billion cubic feet of natural gas would have been required to meet America's packaging needs in 1990. That's enough to meet the energy needs of 100,000 homes for 35 years.
Facts about Plastics
Q: How are plastics made?
A: Plastics consist of building blocks called hydrocarbons, typically derived from petroleum or natural gas. These monomers (small molecules) are bonded into chains called polymers or plastic resins. Different combinations of monomers yield resins with special properties and characteristics.
Q: Why are plastics used in packaging?
A: Packaging serves many purposes, but one of its primary functions is to help protect the quality of goods - ranging from sensitive electronics to fresh and prepared foods - during shipping, handling and merchandising. Plastics are a versatile family of materials that are suitable for a wide range of packaging applications. In many cases, plastics offer the best protection while using minimal resources and creating less waste than alternative materials. In fact, 400 percent more material by weight would be needed to make packaging if there were no plastics, while the volume of packaging would more than double.
Q: Why are plastics used in durable goods?
A: Manufactured items with a useful life of more than three years - cars, appliances, computers, etc. - are called durable goods. Manufacturers of durable goods choose plastics for the following reasons:
1. The automotive industry chooses plastic for its durability, corrosion resistance, ease of coloring and finishing, resiliency, energy efficiency and light weight. Light weight, for instance, translates into lowered handling and transportation costs all down the line. Where a plastic film (as in stretch wrap) can replace a heavy shipping crate or carton, the weight savings can be an order of magnitude or more.
2. Major appliance manufacturers use plastics because of their ease of fabrication and outstanding thermal insulation characteristics, that significantly reduce energy consumption.
3. The building and construction industry uses vinyl siding for homes because of its appearance, durability, ease of installation and energy efficiency. Plastics can reduce energy consumption for the auto, appliance, and building and construction industries, providing a substantial savings in production costs.
Q: Why do we need different kinds of plastics?
A: Copper, silver and aluminum are all metals, yet each has unique properties. You wouldn't make a car out of silver or a beer can out of copper because the properties of these metals are not chemically or physically able to create the most effective final product. Likewise, while plastics are all related, each resin has attributes that make it best suited to a particular application. Plastics make this possible because as a material family they are so versatile.
Six resins account for nearly all of the plastics used in packaging:
• PET (polyethylene terephthalate) is a clear, tough polymer with exceptional gas and moisture barrier properties. PET's ability to contain carbon dioxide (carbonation) makes it ideal for use in soft drink bottles.
• HDPE (high density polyethylene) is used in milk, juice and water containers in order to take advantage of its excellent protective barrier properties. Its chemical resistance properties also make it well suited for items such as containers for household chemicals and detergents.
• Vinyl (polyvinyl chloride, or PVC) provides excellent clarity, puncture-resistance and cling. As a film, vinyl can breathe just the right amount, making it ideal for packaging fresh meats that require oxygen to ensure a bright red surface while maintaining an acceptable shelf life.
• LDPE (low density polyethylene) offers clarity and flexibility. It is used to make bottles that require flexibility. To take advantage of its strength and toughness in film form, it is used to produce grocery bags and garbage bags, shrink and stretch film, and coating for milk cartons.
• PP (polypropylene) has high tensile strength, making it ideal for use in caps and lids that have to hold tightly to threaded openings. Because of its high melting point, polypropylene can be hot-filled with products designed to cool in bottles, including ketchup and syrup. It is also used for products that need to be incubated, such as yogurt.
• PS (polystyrene), in its crystalline form, is a colorless plastic that can be clear and hard. It can also be foamed to provide exceptional insulation properties. Foamed or expanded polystyrene (EPS) is used for products such as meat trays, egg cartons and coffee cups. It is also used for packaging and protecting appliances, electronics and other sensitive products.
Q: What about CFCs (Cloro Floro Carbon)?
A: Most (nearly 70 percent) of polystyrene foam products never were made with chlorofluorocarbons (CFCs). In the late 1980s, those few polystyrene manufacturers that used them announced the voluntary phaseout of CFCs.
Courtesy: SPI
A: Plastics consist of building blocks called hydrocarbons, typically derived from petroleum or natural gas. These monomers (small molecules) are bonded into chains called polymers or plastic resins. Different combinations of monomers yield resins with special properties and characteristics.
Q: Why are plastics used in packaging?
A: Packaging serves many purposes, but one of its primary functions is to help protect the quality of goods - ranging from sensitive electronics to fresh and prepared foods - during shipping, handling and merchandising. Plastics are a versatile family of materials that are suitable for a wide range of packaging applications. In many cases, plastics offer the best protection while using minimal resources and creating less waste than alternative materials. In fact, 400 percent more material by weight would be needed to make packaging if there were no plastics, while the volume of packaging would more than double.
Q: Why are plastics used in durable goods?
A: Manufactured items with a useful life of more than three years - cars, appliances, computers, etc. - are called durable goods. Manufacturers of durable goods choose plastics for the following reasons:
1. The automotive industry chooses plastic for its durability, corrosion resistance, ease of coloring and finishing, resiliency, energy efficiency and light weight. Light weight, for instance, translates into lowered handling and transportation costs all down the line. Where a plastic film (as in stretch wrap) can replace a heavy shipping crate or carton, the weight savings can be an order of magnitude or more.
2. Major appliance manufacturers use plastics because of their ease of fabrication and outstanding thermal insulation characteristics, that significantly reduce energy consumption.
3. The building and construction industry uses vinyl siding for homes because of its appearance, durability, ease of installation and energy efficiency. Plastics can reduce energy consumption for the auto, appliance, and building and construction industries, providing a substantial savings in production costs.
Q: Why do we need different kinds of plastics?
A: Copper, silver and aluminum are all metals, yet each has unique properties. You wouldn't make a car out of silver or a beer can out of copper because the properties of these metals are not chemically or physically able to create the most effective final product. Likewise, while plastics are all related, each resin has attributes that make it best suited to a particular application. Plastics make this possible because as a material family they are so versatile.
Six resins account for nearly all of the plastics used in packaging:
• PET (polyethylene terephthalate) is a clear, tough polymer with exceptional gas and moisture barrier properties. PET's ability to contain carbon dioxide (carbonation) makes it ideal for use in soft drink bottles.
• HDPE (high density polyethylene) is used in milk, juice and water containers in order to take advantage of its excellent protective barrier properties. Its chemical resistance properties also make it well suited for items such as containers for household chemicals and detergents.
• Vinyl (polyvinyl chloride, or PVC) provides excellent clarity, puncture-resistance and cling. As a film, vinyl can breathe just the right amount, making it ideal for packaging fresh meats that require oxygen to ensure a bright red surface while maintaining an acceptable shelf life.
• LDPE (low density polyethylene) offers clarity and flexibility. It is used to make bottles that require flexibility. To take advantage of its strength and toughness in film form, it is used to produce grocery bags and garbage bags, shrink and stretch film, and coating for milk cartons.
• PP (polypropylene) has high tensile strength, making it ideal for use in caps and lids that have to hold tightly to threaded openings. Because of its high melting point, polypropylene can be hot-filled with products designed to cool in bottles, including ketchup and syrup. It is also used for products that need to be incubated, such as yogurt.
• PS (polystyrene), in its crystalline form, is a colorless plastic that can be clear and hard. It can also be foamed to provide exceptional insulation properties. Foamed or expanded polystyrene (EPS) is used for products such as meat trays, egg cartons and coffee cups. It is also used for packaging and protecting appliances, electronics and other sensitive products.
Q: What about CFCs (Cloro Floro Carbon)?
A: Most (nearly 70 percent) of polystyrene foam products never were made with chlorofluorocarbons (CFCs). In the late 1980s, those few polystyrene manufacturers that used them announced the voluntary phaseout of CFCs.
Courtesy: SPI
The Safety of Plastics in Food Packaging
• Plastics in food packaging help keep our food fresh and safe, and protects against spoilage. Plastic packaging provides a hygienic and safe environment for foods and medicine by protecting against contamination while keeping foods fresh throughout use. It also often provides tamper-evident features (shrink bands, tear strips, etc.) for food and medicine.
• Thanks to plastics, a wide range of foods - from fresh produce to dairy products to beverages - can be transported over long distances and stored safely without compromising the quality of the product. This also helps prevent food waste.
• Plastics allow packaging to perform many necessary tasks and provide properties including strength and stiffness, barrier to oxygen transmission and moisture, resistance to food component attack, and flexibility.
• Innovation in rigid plastic packaging adds quality and a variety of new dimensions to food packaging. Rigid plastics can be shaped to the contour of the product and thus provide improved visibility.
• Plastics make possible both rigid and flexible packages for long shelf-life foods including several that rely on high barrier properties to restrict penetration by oxygen and flavor loss, thus supporting ambient shelf storage.
• Modified atmosphere packages, made possible through the unique properties of plastic, are used in packaging fruits, vegetables, baked goods, fresh and processed meats, and cooked poultry. Through this process, fresh produce and other food products can be packaged in controlled atmospheres that maintain the carbon dioxide/oxygen ratio at its optimum level, thus greatly extending the shelf life of these foods.
• The advent of new technology (e.g., multilayer package applications) is allowing high-barrier food and beverage bottles, pouches and containers to prolong the shelf life of products such as beer, ketchup, juice and milk.
• The use of plastics in aseptic packaging significantly increases the non-refrigerated shelf life and availability of many perishable products making them more readily available in the hot, humid climate of the developing world and dramatically improving the diets of the people who live there.
• Thanks to plastics, a wide range of foods - from fresh produce to dairy products to beverages - can be transported over long distances and stored safely without compromising the quality of the product. This also helps prevent food waste.
• Plastics allow packaging to perform many necessary tasks and provide properties including strength and stiffness, barrier to oxygen transmission and moisture, resistance to food component attack, and flexibility.
• Innovation in rigid plastic packaging adds quality and a variety of new dimensions to food packaging. Rigid plastics can be shaped to the contour of the product and thus provide improved visibility.
• Plastics make possible both rigid and flexible packages for long shelf-life foods including several that rely on high barrier properties to restrict penetration by oxygen and flavor loss, thus supporting ambient shelf storage.
• Modified atmosphere packages, made possible through the unique properties of plastic, are used in packaging fruits, vegetables, baked goods, fresh and processed meats, and cooked poultry. Through this process, fresh produce and other food products can be packaged in controlled atmospheres that maintain the carbon dioxide/oxygen ratio at its optimum level, thus greatly extending the shelf life of these foods.
• The advent of new technology (e.g., multilayer package applications) is allowing high-barrier food and beverage bottles, pouches and containers to prolong the shelf life of products such as beer, ketchup, juice and milk.
• The use of plastics in aseptic packaging significantly increases the non-refrigerated shelf life and availability of many perishable products making them more readily available in the hot, humid climate of the developing world and dramatically improving the diets of the people who live there.
Friday, September 10, 2010
High performance duct by Thermoplastic - Very first time !!
A highly successful metal replacement application is a new supercharger outlet elbow/duct made of DuPont™ Zytel® HTN PPA from DuPont Performance Polymers. The intermediary duct for the outboard engine captures all the value of engineering polymers – parts consolidation, high-temperature resistance, lower weight and reduced cost – with no performance tradeoffs. The high-performance duct is the first use of a thermoplastic in a pressure-charged air handling duct for outboard engines. The thermoplastic duct, which delivers charged air from the supercharger to the charged air cooler, operates in an extremely hot environment (up to 175°C). Zytel® HTN51-series resin, a high-temperature resistant PPA, meets the stringent thermal requirements, replacing thin-gauge 1018 formed steel which also required a heat sleeve for added thermal protection. The 7-in-long, 2.4-in dia. thermoplastic duct doesn’t require a heat shield and provides a cooler touch. The conversion from metal to Zytel® HTN PPA reduces the number of parts (six to five) and lowers associated part costs. The plastic design eliminates the corrosion layer and a related painting step which was required on the steel version and also offers more pleasing aesthetics (better surface appearance). Also eliminated was a failure of the metal to repeatedly cut the rubber cuffs at the end of the duct. Known for its exceptional temperature and load resistance, Zytel® HTN resin also provides 15% faster cycles than competitive PPA materials. The material’s high-glass transition temperature of 145°C facilitates better flow and faster part ejection. The supercharger elbow duct was manufactured by using a rotating core to produce a gentle, curved design which helped minimize pressure drops. The injection molding process also produced parts with greater dimensional stability than those made of formed steel.
The plastic supercharger outlet duct is used on all four- and six-cylinder models of Mercury Marine’s flagship Verado supercharged outboard engine. Mercury was an early adopter of engineering thermoplastics in outboard engine components and has increasingly used DuPont materials for their unique benefits over traditional materials like metal.
The plastic supercharger outlet duct is used on all four- and six-cylinder models of Mercury Marine’s flagship Verado supercharged outboard engine. Mercury was an early adopter of engineering thermoplastics in outboard engine components and has increasingly used DuPont materials for their unique benefits over traditional materials like metal.
World's first methanol-to-olefins unit
The world's first methanol-to-olefins unit to be operated on a commercial scale has started up in China. The plant using the combined DMTO methanol-to-olefins technology of SYN Energy Technology Co. Ltd. and Lummus Technology has successfully started-up in Baotou, China. The plant is owned by China Shenhua Coal to Liquid and Chemical Company Ltd.
The breakthrough technology enables licensees to produce olefins (ethylene and propylene) from methanol. The plant is designed to produce 600,000 tpa of olefins from methanol. On spec ethylene and propylene product were achieved less than 72 hours after methanol was introduced to the unit.
The breakthrough technology enables licensees to produce olefins (ethylene and propylene) from methanol. The plant is designed to produce 600,000 tpa of olefins from methanol. On spec ethylene and propylene product were achieved less than 72 hours after methanol was introduced to the unit.
Indian Plastic Industry
The Plastics Industry in India has made significant achievements ever since it made a modest but promising beginning by commencing production of Polystyrene in 1957. The chronology of manufacture of polymers in India is summarised as under:-
- 1957-Polystyrene
- 1959-LDPE
- 1961-PVC
- 1968- HDPE
- 1978-Polypropylene
The potential Indian market has motivated Indian entrepreneurs to acquire technical expertise, achieve high quality standards and build capacities in various facets of the booming plastic industry. Phenomenal developments in the plastic machinery sector coupled with matching developments in the petrochemical sector, both of which support the plastic processing sector, have facilitated the plastic processors to build capacities to service both the domestic market and the markets in the overseas.
The plastic processing sector comprises of over 30,000 units involved in producing a variety of items through injection moulding, blow moulding, extrusion and calendaring. The capacities built in most segments of this industry coupled with inherent capabilities has made us capable of servicing the overseas markets.
The economic reforms launched in India since 1991, have added further fillip to the Indian plastic industry. Joint ventures, foreign investments, easier access to technology from developed countries etc have opened up new vistas to further facilitate the growth of this industry.
- 1957-Polystyrene
- 1959-LDPE
- 1961-PVC
- 1968- HDPE
- 1978-Polypropylene
The potential Indian market has motivated Indian entrepreneurs to acquire technical expertise, achieve high quality standards and build capacities in various facets of the booming plastic industry. Phenomenal developments in the plastic machinery sector coupled with matching developments in the petrochemical sector, both of which support the plastic processing sector, have facilitated the plastic processors to build capacities to service both the domestic market and the markets in the overseas.
The plastic processing sector comprises of over 30,000 units involved in producing a variety of items through injection moulding, blow moulding, extrusion and calendaring. The capacities built in most segments of this industry coupled with inherent capabilities has made us capable of servicing the overseas markets.
The economic reforms launched in India since 1991, have added further fillip to the Indian plastic industry. Joint ventures, foreign investments, easier access to technology from developed countries etc have opened up new vistas to further facilitate the growth of this industry.
Plastic Fuel Tanks !!
New Developments for Plastic Fuel Tanks
Plastic fuel tanks have gained widespread use in applications that include automotive, marine, construction, agriculture, power equipment, and all-terrain vehicles. Plastic fuel tanks are desirable because they can be formed in complicated shapes, are corrosion resistant, are light weight, have high puncture resistance, and are relatively low cost. Fluoro-Seal has developed two new technologies that can make plastic fuel tanks even better. One technology increases the fire resistance of plastic tanks, which enhances safety. The other technology increases the barrier properties of plastic tanks, which reduces the permeation of fuel through tank walls and enables plastic tanks to comply with current and pending environmental regulations.
Increased Fire Resistance
When a current version plastic fuel tank is exposed to fire, the plastic either melts or decomposes and allows the contents to flow out and add fuel to the fire. To buy time in case of a fire, plastic fuel tanks used in marine applications are molded in crosslinked resin. Crosslinked plastic does not melt when heated. But as the temperature of the plastic increases, the plastic begins to decompose and burn. When exposed to a fire, a non-crosslinked plastic tank may fail in approximately 11/2 minutes and a crosslinked plastic tank of the same size and shape may fail in 21/2 - 3 minutes.
Because of U.S. Coast Guard requirements concerning survivability of fuel tanks in a burn test, only crosslinked resins are used in marine applications. Clearly it is desirable to make plastic fuel tanks that can endure fires even longer before they fail.
Fluoro-Seal has developed a method for modifying plastic tanks such that they have an intumescent coating on the outside surface. When these tanks are exposed to fire, the intumescent coating is converted into a thick, insulating layer of noncombustible foam. This char layer is extremely effective in insulating the plastic such that it barely gets warm when exposed to fire. Using the Coast Guard test protocol, it was demonstrated that plastic fuel tanks made in noncrosslinked resin and coated with the intumescent coating can survive the test longer than is mandated by the requirements.
Barrier to Permeation Loss
One characteristic of plastic fuel tanks is that they allow small amounts of fuel to permeate through the tank walls. The amount of fuel lost this way is quite small and is not usually missed by the owner. However, if one adds up the small amounts of hydrocarbon losses from the hundreds of millions of plastic fuel tanks in use in the U.S., this represents a substantial amount of air pollution. Therefore, various Federal and State agencies continue to enact legislation to increasingly reduce this source of pollution. In fact, new legislation is scheduled for enactment in the next few years that will affect millions of plastic fuel tanks made each year for various non-automotive applications. Existing technologies for increasing the fuel-barrier properties appear to not be sufficiently effective for all of these tanks. Fluoro-Seal has developed two different types of technologies for significantly increasing the barrier properties of plastic fuel tanks. The company is working with tank manufacturers and plastic resin suppliers to optimize these technologies. With the combination of these two different approaches, the company is confident that all types of plastic fuel tanks, independent of the molding process used to make them, can be made compliant with new evaporative loss regulations.
Courtesy:http://www.fluoroseal.com
Tuesday, September 7, 2010
Conversion of Plastics waste into Liquid Fuel
A research-cum-demonstration plant was set up at Nagpur, Maharashtra for conversion of waste plastics into liquid fuel. The process adopted is based on random de-polymerization of waste plastics into liquid fuel
in presence of a catalyst. The entire process is undertaken in closed reactor vessel followed by condensation, if required. Waste plastics while heating upto 2700 C to 3000 C convert into liquid-vapour state, which is
collected in condensation chamber in the form of liquid fuel while the tarry liquid waste is topped-down from the heating reactor vessel. The organic gas is generated which is vented due to lack of storage facility. However, the gas can be used in dual fuel diesel-generator set for generation of electricity. The process includes the steps shown ahead:
Environment related observations during the process
❯ There are no liquid industrial effluents and no floor washings as it is a dry process.
❯ There are no organized stack and process emissions.
❯ Odour of volatile organics has been experienced in the processing area due to some leakages or lack of proper sealing
❯ Absolute conversion of liquid-vapour was not possible into liquid, some portion of gas (about 20%) is connected to the generator. However, the process will be improved in full-scale plant.
❯ PVC plastics waste is not used and if used, it was less than 1%. In case PVC is used, the chlorine can be converted into hydrochloric acid as a by-product.
❯ The charcoal (charcoal is formed due to tapping of tarry waste) generated during the process has been analysed and contain heavy metals, poly aromatic hydrocarbon (PAH) which appears to be hazardous in nature. The source of metals in charcoal could be due to the presence of additives in plastics and due to multilayer and laminated plastics.
❯ Monitoring of process fugitive emissions in the work area as well as emissions from the engines/diesel generator sets is necessarily required (where this liquid fuel is used) for various parameters such as CO, HCl,
Styrene, Benzene, VOCs.
in presence of a catalyst. The entire process is undertaken in closed reactor vessel followed by condensation, if required. Waste plastics while heating upto 2700 C to 3000 C convert into liquid-vapour state, which is
collected in condensation chamber in the form of liquid fuel while the tarry liquid waste is topped-down from the heating reactor vessel. The organic gas is generated which is vented due to lack of storage facility. However, the gas can be used in dual fuel diesel-generator set for generation of electricity. The process includes the steps shown ahead:
❯ There are no liquid industrial effluents and no floor washings as it is a dry process.
❯ There are no organized stack and process emissions.
❯ Odour of volatile organics has been experienced in the processing area due to some leakages or lack of proper sealing
❯ Absolute conversion of liquid-vapour was not possible into liquid, some portion of gas (about 20%) is connected to the generator. However, the process will be improved in full-scale plant.
❯ PVC plastics waste is not used and if used, it was less than 1%. In case PVC is used, the chlorine can be converted into hydrochloric acid as a by-product.
❯ The charcoal (charcoal is formed due to tapping of tarry waste) generated during the process has been analysed and contain heavy metals, poly aromatic hydrocarbon (PAH) which appears to be hazardous in nature. The source of metals in charcoal could be due to the presence of additives in plastics and due to multilayer and laminated plastics.
❯ Monitoring of process fugitive emissions in the work area as well as emissions from the engines/diesel generator sets is necessarily required (where this liquid fuel is used) for various parameters such as CO, HCl,
Styrene, Benzene, VOCs.
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