Biodegradable packaging materials

Russo M, O Sullivan C et al (2009) The anaerobic degradability of thermoplastic starch Polyvinyl alcohol blends Potential biodegradable food packaging materials. Bioresour Technol 100 1705-1710... 

One of the first applications of biodegradable materials is based on the cooked, extruded, and expanded starch known from the food and chemical sectors (Fig. 14.23). Starch is cooked with water in the extruder and chemically modified as necessary or mixed with plasticizers, then expanded to a starch foam and dried. The extrudate is ground so that the functional properties thus created can be used in the food/chemicals sector. The foamed, cut, and dried extrudate is the end product for loose-fill packaging applications. The degree of expansion is a measure of the foam texture. It increases strongly with product temperature at the die, helped by a higher specific mechanical energy input. However, both measures increase the water-solubility of the product. 

Synthetic biodegradable polyesters are used mainly as specialty materials for paper coating, fibres, and garbage bags and sacks. They are also showing up in thermoformed packaging as functional adjuncts to lower-cost biodegradable materials. 

Synthetic biodegradable polymers are also finding a growing number of applications in thermoformed packaging, usually to provide a moisture barrier layer to lower-cost biodegradable materials. 

Guilbert, S., and Gontaid, N. (1995). Edible and biodegradable food packaging. In P. Ackerman, M. Jagerstad, and T. Ohlsson (eds.). Foods and Packaging Materials-Chemical Interactions. The Royal Society of Chemistry, Cambridge, pp 159-168. 

Already there are certain restrictions for certain non-biodegradable plastic packaging materials (the US Plastics Pollution Research and Control Act of 1987, Public Law 100-220 and the Annex of the MARPOL (marine pollution) Convention - the International Convention for the Prevention of Pollution from Ships which prohibit the disposal of plastics at sea, which allowed the US Navy promote the development of aquatic biodegradable plastics at sea. 

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