Starch-based polymer, commercialization

Table 2.8. Starch-based polymers commercially available...

Just as with most other polymers, processability is an important parameter to commercial success for biodegradable polymers. For example, some grades of starch-based polymers can be processed on standard low-density poly(ethylene) extension equipment for making blown or cast film. Other grades... 

A particular mention goes to Mater-Bi, produced by Novamont, who have revolutionised starch-based biomaterials for two decades. The commercial success of this biodegradable and biocompostable plastic relies on two main factors the scale economy that allows the reduction of costs, and the diversity of formulations to develop different end products (plastic bags, tableware, toys, etc.). More than 210 references in Chemical Abstracts are available on this (registered) keyword, and the number of patents related to different formulations and developments is also impressive. Mater-Bi can be essentially described as a blend of starch with a small amount of other biodegradable polymers and additives. The actual compositions are still known only by a very few people. 

These discoveries provided the technology base for commercialization efforts of starch-based plastics by the Novon division of the Warner-Lambert Company.157,158 The thermoplastic compositions were based on blends of destructurized starch and various hydrophilic polymers, such as ethylene-vinyl alcohol copolymers (EVOH). Hydrophobic polymers and additives, such as plasticizers and lubricants, could also... 

Green plastics comprise only a very small part (less than 1%) of today s plastics. They do, however, make up a significant part of some specialty, niche markets starch-based loose-fill packaging now constitutes 30% of the loose-fill packaging market. The plastics described here are those currently commercially available, and are limited mainly to those available in the United States. Manufacturers are named only for illustrative purposes the list is not intended to be comprehensive. The plastics materials are described generically, with respect to the major polymer constituent(s) for each generic type there are likely to be many specific formulations. Brief mention is made, at the end, of some materials that have been studied in the laboratory. Biomedical applications are described separately (see Biodegradable Polymers, Medical Applications). 

Second-generation biodegradable polymers were commercially introduced around 1990 and are represented by the starch-based products offered by Novamont (Mater-Bi ) and by several families of polyesters. One of these polyesters, poly(e-caprolactone), has been commercially available for more than twenty years other biodegradable polyesters, which have been commercialized very recently, include poly(lactic acid) and other aliphatic polyesters. As a result of plant investments made by Cargill-Dow EEC (now NatureWorks EEC) and others, biodegradable polyesters should become more affordable very soon. 

The reference commercial starch-based biodegradable polymers are marketed by Novamont in Italy imder the name Mater-Bi . This starch-based technology permits going beyond conventional compounding. In the presence of different synthetic polymers, starch can undergo a thermoplastic transformation up to destructurisation the destructurised starch composites can reach starch contents higher than 50% [83]. 

FIGURE 21 Commercial bio-based polymers (a) starch copolymer based biodegradable carry bag, (b) 50-50 film blend of poly lactic acid and petroleum-based materials for packaging cheese snacks, (c) packaging blister made from cellulose acetate, (d) biodegradable bottle on sale in Britain, (e) PLA yoghurt cup, and (f) 100% degradable sandwich box. 

The non-biodegradable and non-renewable nature of plastic packaging has led to a renewed interest in packaging materials based on biopolymers derived from renewable sources. Such biopolymers include naturally occurring proteins, cellulose, starches, and other polysaccharides and those synthesized chemically from naturally derived monomers such as lactic acid. Commercialization of these bio-based polymers has already begun. Naturewoiks, LLC (Minnetonka, MN) manufactures polylactide from... 

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