Biodegradeable plastics

Biodegradable Plastics and Polymers, Y. Doi and K. Eukuda, eds.. Studies in Poljmer Science, Vol. 12, Elsevier, Amsterdam, the Netherlands, 1994. 

Some 50 years later, in the 1990s Bayer produced their BAK polyesteramides by co-reacting either hexamethylene diamine or e-caprolactam with adipic acid and butane glycol. These materials do have sufficient regularity to be crystallisable and are of interest as biodegradable plastics and are discussed further in Chapter 31. 

Chapters 10 to 29 consisted of reviews of plastics materials available according to a chemical classification, whilst Chapter 30 rather more loosely looked at plastics derived from natural sources. It will have been obvious to the reader that for a given application plastics materials from quite different chemical classes may be in competition and attempts have been made to show this in the text. There have, however, been developments in three, quite unrelated, areas where the author has considered it more useful to review the different polymers together, namely thermoplastic elastomers, biodegradable plastics and electrically conductive polymers. 

A novel non-petroleum based biodegradable plastic produced from sugar based agricultural raw materials as sweet sorghum, sugarcane and molasses, having potential properties comparable with conventional or synthetic plastics, is under development and could lower the contribution of plastic wastes to municipal landfills at about 20% of the total waste by volume and 10% by weight and can achieve a satisfactory for the environmental imperative. 

Evan, J.D., Sikdar, S.K., 1990. Biodegradable plastic An idea whose time has come. 

Potts, J. E., Clendinning, R. A., and Cohen, S., Biodegradable plastic containers for seedling transplants, Soc. Plast. 

Yoon SC, Song JJ, Kim TU (1994) In Doi Y, Fukuda K (eds) Biodegradable plastics and polymers. Elsevier, Amsterdam London New York Tokyo, p 400... 

Although for many decades the primary interest in the production of PHAs has been as a source of biodegradable plastics and elastomers, PHA synthesis in plants has opened novel avenues for the use of these polymers in both plant biotechnology and basic research. 

One of the main barriers to the widespread use of biodegradable plastics is their higher production cost compared to petroleum plastics. For example, whereas the cost of most commodity plastics, such as polypropylene, is well below 1 US /kg, the costs of some of the cheapest biodegradable plastics on the... 

All of these factors mean that production of PHA in plants will likely be more expensive than starch. However, considering that starch costs about 0.25 US /kg, even tripling the production cost of PHA compared to starch would make PHA in plants at least five times cheaper than PHA obtained from bacterial fermentation and most likely the cheapest biodegradable plastic made from renewable resources. 

The most well known application of PHB and poly(3HB-co-3HV) is as substitute for conventional, non-biodegradable plastics used for packaging purposes and derived products [21, 115, 116]. Single-use bottles for shampoos, cosmetics and biodegradable motor-oil have been manufactured from these biopolyesters by common molding techniques. Containers and cups for food products were developed similarly, and bags have been produced from blown films of the material. 

Report by the study committee for the practical use of biodegradable plastics The age of new plastics March 1995... 

Although most of the polymeric objects are combustible, incineration is not always a feasible method of disposal because of attendant air pollution => Biodegradable plastics . 

Fig. 9.3 Degradation of a biodegradable plastic film after soil solarization in a field experiment in Southern Italy (courtesy of dr Donato Castronuovo)...

Castronuovo D, Candido V, Margiotta S, Manera C, Miccolis V, Basile M, D Addabbo T (2005) Potential of a corn starch-based biodegradable plastic film for soil solarization. Acta Hort (ISHS) 698 201-206... 

Russo G, Candura A, Scarascia-Mugnozza G (2005) Soil solarization with biodegradable plastic film two years of experimental tests. Acta Hort (ISHS) 691 717-724... 

Patel, M. (2005). Environmental life cycle comparisons of biodegradable plastics. Chapter 13. In Handbook of Biodegradable Polymers, ed. Bastioli, C. Shawbury, UK Rapra Technology Ltd. pp. 431 184. 

The ability of a degradable plastic to decay depends on the structure of its polymer chain. Biodegradable plastics are often manufactured from natural polymers, such as cornstarch and wheat gluten. Micro-organisms in the soil can break down these natural polymers. Ideally, a biodegradable plastic would break down completely into carbon dioxide, water, and biomass within six months, just like a natural material. 

---