Other Biobased Plastics

There continue to be efforts to develop additional biobased plastics. Generally these are produced by conventional polymerization methods from biologically derived monomers (usually produced by fermentation from starch, sugar, or cellulose). And, the resulting plastics are most often not biodegradable. 

Many of these new plastics are in the polyester family. One that is getting attention is PEF, polyethylene furanoate. Avantium opened a PEE pilot plant in the Netherlands in 2011. PEF reportedly is similar to PET in performance, but is 100% biobased [10]. Polybutylene terephthalate (PBT) is available as a partially biobased plastic, from biobased 1,4-butanediol and petro-based terephthalic acid. Polybutylene succinate (PBS) is similarly made from biobased succinic acid and petro-based terephthalic acid. Poly(trimethylene terephthalate) (PTT) can be made from biobased 1,3-propanediol with, again, petro-based terephthalic acid. 

Some members of the nylon family are also readily produced from biobased monomers. Examples include nylon 6 from biobased caprolactam and nylon 66 from biobased adipic acid. 

There is also interest in other sources of natural polymers that are both biobased and biodegradable. Starting materials include chitin, chitosan, casein, hemicellu-lose, and others. None of these materials have yet reached the point of commercial applications as packaging materials. 

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Table 8.3 Overview of other biobased plastics on the market according to [16],...

Q.5.7 The density of biobased PP is greater than 1.0 like other biobased plastics. T or F ... 

Although Coca-Cola s PlantBottle [39] is marketed as a drop-in replacement for its petroleum counterpart, other biobased plastics are not. Contamination by polylactic acid (PLA), a biosourced and compostable alternative to PET, is often cited as a major concern for PET recyclers. It is difficult to separate PLA from PET in most recychng facilities. While the technology exists to separate PLA from PET, it is costly and not commonly used [40]. 

Polyhydroxybutyrate, polyhydroxyvalerate, and blends have melting temperatures of 145-175°C [19]. Early results indicate that these microorganism-based plastics are processible in traditional thermoforming equipment. Other biobased plastics include modified polyesters and older plastics, such as polystarches, plastics from gluten- and gliadin-based amino acids, casein, and, of course, cellulosics. Acceptance of biobased plastics depends on their long-term... 

This third edition fixes some of the errors that, despite our best efforts, found their way into the previous editions. Unfortunately, we re sure that we have still not found them all We have expanded and updated the discussion of biobased plastics such as PLA and PHA, plastics recycling, life cycle assessment, and a variety of other topics. 

Biodegradable plastics based on lactic acid have been available on a small scale for many years. They have been used In applications such as medical implants, but their high price was a deterrent to widespread use in lower value applications such as packaging. However, new technologies for production of lactide monomers greatly lowered costs, making the polymers much more competitive. Generally, the lactic acid is obtained from corn or other biobased materials by a fermentation process, and then chemical synthesis is used to produce the polymer from the lactic acid or lactide monomers. 

Other Polysaccharides. Some biodegradable or biobased plastics are made by starting with cellulose and modifying it to make it thermoplastic. For example, the Japanese company Ebara Jitsugyo, Ltd. (El CO), manufactures several products based on cellulose acetate that are claimed to be biodegradable. ... 

Several conventional plastics can be produced from organic sources. Biobased polyethylene and biobased PET resins are currently available. Other plastics can be produced with biobased sources Table 5.1 lists the biobased plastics that are commercially available. 

Sustainable plastics are those plastics made with lower energy, lower carbon footprint, lower waste, and lower pollution than conventional plastics. Plastics that are made from plants or biobased sources and from recycled plastics can be made with lower energy, lower carbon footprint, lower waste, and lower pollution than conventional plastics. Biobased polyethylene, propylene, and PET can be made from sugarcane or other agricultural materials. Biobased plastics can be made with nearly identical mechanical properties as conventional petroleum-based plastics and can be manufactured on identical plastics processing equipment. 

Plastic packaging can be produced with sustainable plastics through the use of the definitions presented above. Plastic packaging products account for approximately 30% of the plastics sold in the United States, and approximately 27% of the plastic products sold in Europe (Beswick and Dunn 2002). Sustainable plastic packaging can be made from recycled plastics or biobased plastics, like PHA, PLA, starch, and others. Life cycle assessments can be used to compare environmental impacts of using recycled or biobased plastic materials for plastic packaging products. 

Biobased plastics can be used for coatings for drug delivery, bio-absorbable, and other medical devices. Biopolymers are made from non-toxic materials that are compatible with human tissues. PLA, PGA, and PCL are commonly used in biomedical devices (Cheng et al. 2009). The biopolymers are degraded with simple hydrolysis of the ester bonds without the use of enzymes that prevent inflammation. The biodegraded bio-products are eliminated from the body through normal cellular activity and urine. PLA can be used as a bio-absorbable polymer for resorbable plates and screws (Lasprilla et al. 2012). PLA can provide a... 

Biobased plastics can be used for coatings for drug delivery, bio-absorbable, and other medical devices. Biopolymers are made from non-toxic materials that are compatible with human tissues. PLA, PGA, and PCL are commonly used in biomedical devices. 

Polyhydroxybntyrate/valerate (PHBV), one of the truly biodegradable non-cellulose based plastics, is a bacterially grown polyester with properties similar to PP. It was sold nnder the name Biopol. PHPB is one member of family of poly hydroxyalkanoates (PHAs) prodnced by microbes from sugars or other biobased materials. Metabohx PHAs are reported to be better water vapor barriers than most biodegradable plastics. 

Natural soybean oil is too viscous and reactive to atmospheric oxygen to be used in many biobased product applications. These limitations must be overcome for soybean oil to be used in fuels, cosmetics, and lubricants, but on the other hand, soybean oil is not sufficiently reactive to be used in most paints and coatings. Important end-use categories for which economic data exist include fatty acids, paints and varnishes, resins and plastics, drying-oil products, and other industrial products. Coating vehicles (paints and varnishes) and epoxidized oils (resins and plastics) comprise 50% of... 

The term soy proteins typically refers to processed, dry soybean products other than animal feed meals. Many types of protein products are produced for use in human and pet foods and in milk replacers and starter feeds for young animals. Some soy protein products are also used in biobased products (e.g., plastics, adhesives, paper coatings), and others are being a ressively researched by industry and public-sector research institutions, especially recendy as petroleum prices rise (Johnson, 1992a ISU, 1994). The many soy protein products and their uses are shown in Fig. 19.3. 

The phenomena of fashion aside, the aim of this chapter is to touch on the increasingly marked impact of plastics on our environment, but also and above all to put forward solutions to minimize the footprint of such materials. Maity publications on the subject are available, to which readers can refer if they wish for further detail on these concepts pUV 04, ROB 03], After a few general points about the lifecycle of plastics, two concrete examples of ecoplastics are presented one based on biobased materials, and the other solely on recycled synthetic materials. 

Since the early 2000s, plant-derived biobased fibrous fillers have been frequently used for the reinforcement of PLA-based materials. A well known and frequently used plant-derived fibrous filler is kenaf. Like the case of pollen as an additive, the wettability between PLLA and kenaf should be improved by the addition of a compatibilizer. Other fibrous materials are cellulose fibrous materials or fibres [383,384], cellulose whiskers [385], recycled cellulose fibre [386], cotton fibre [387], sugar beet pulp [388], flax [389], bamboo fibre [390], kenaf [391-393], papyrus [394], hemp fibre [395], cuphea and lesquerella [396], ramie [397], rice straw fibre [398], red algae fibre [399], miscanthus fibre [400], abaca fibre [401], milkweed [402], wood fibre [403] and recycled newspaper fibre [404], Poly(L-lactic acid) fibre can also be used to reinforce soft plastics such as PCL [405],... 

Sustainability has many definitions. One way to think of it is meeting the needs of the present without compromising the ability of future generations to meet their needs (defined by the World Commission on Environment and Development held by the United Nations in 1983). The concept of sustainability is that we should synchronize our consumption of natural resources with the Earth s production - in other words, using up natural resources at the same rate at which they are produced. Compared to traditional polymers typically made from petroleum and other fossil resources such as natural gas, sustainable polymers are fuUy or partially biobased and/or biodegradable or compostable. They are bioplastics made from renewable resources (biomass) and can be broken down faster than traditional plastics. Sustainable polymers could also protect our Earth by offering a reduced carbon footprint, a reduced use of fossil resources, and improved end-of-life options. 

The three most common biobased biodegradable polymers are PLA, PHA, and TPS. PLA, PHA, and TPS can be made into plastic containers, packaging, bags, and bottles. All three biobased polymers can be processed with traditional plastics processing equipment. Polyhydrox-yalkanoates can be made from over 100 monomers based on P3HB, P4HB, PHB, and PHV. PHA is produced in the cells of several types of bacteria. Polylactide, or polylactic acid, is made from starch and bacteria. Thermoplastic starch is a blend of starch and other additives. 

Life cycle assessment (LCA) can be used to determine the environmental impacts of producing the biobased polyethylene. The LCA will consider the energy and GHG emission for producing biobased polyethylene from the raw materials to the plastic pellet. The cradle-to-factory gate approach can he useful for plastic packaging, bags, and other products. The cradle-to-gate LCA of biobased polyethylene and petroleum-based polyethylene are Usted in Table 5.3 (Hunter et al. 2008). 

Polyethylene terephthalate (PET) plastic can also be made from plant sources. PET is typically produced from terephthalic acid and monoethylene glycol (MEG) that are made from petroleum products. MEG can also be fermented from sugarcane, corn, soy, or other organic ingredient. Biobased PET, then, can be produced with approximately 30% from organic sources and 70% from petroleum sources. Coca-Cola, Eord Motor, Heinz, Nike, and Proctor Gamble combined forces in a consortium to develop a 100% plant-based PET product. The plant-based PET consortium will collaborate on PET research projects... 

DIN CEN/TS 16137 DIN SPEC 91236 Measuring the biobased carbon content of plastics and other polymers... 

This technical specification provides reference test and calculation methods for determining the biobased carbon content of plastics and other polymers that contain organic carbon. It is based on the carbon methods described in EN 15440 and ASTM D6866. CEN/TS 16137 specifies three test methods ... 

Fillers are an extremely diverse group of materials. They can be minerals, metals, ceramics, biobased (e.g., plant matter), gases, liquids, or even other polymers. Minerals alone account for well over 4000 distinct species. Any particulate material added to a plastic will behave like a filler. For example, antiblock, pigments, impact modifiers, nucleating agents, antioxidant crystals, and numerous other additives will affect the mechanical and other properties of polymers in the same way that filler particles do. Consequently, it is vital to understand... 

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