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LITERATURE REVIEW THE BIODEGRADABILITY OF STARCH-BASED PLASTICS

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Introduction

LITERATURE REVIEW - THE BIODEGRADABILITY OF STARCH-BASED PLASTICS Introduction The biodegradability, or rather, the non-biodegradability of conventional petroleum-based plastics is a pressing environmental issue. Approximately ten million tons of plastic products are discarded each year (Halley et al. 2001). Reusing and recycling plastics have been the first steps in combating the amount of municipal waste that is produced every day. However, mountains of synthetic waste are still generated at a dangerous rate despite efforts to reuse and recycle. A piece of petroleum-based plastic takes approximately 200 years to decompose naturally. As the demand for plastic products continues to rise, so does the pressure of finding a more environmentally-friendly alternative to conventional petroleum-based plastics. The search for an alternative has led researchers to develop biodegradable plastic blends from organic matter such as corn or potato starch. However, progress in the development of starch-based degradable plastics is slow and there is doubt as to whether degradable plastics are truly feasible. Degradable plastics are usually not as durable as petroleum-based plastics, also, and the breakdown products may be toxic to the environment. ...read more.

Middle

Novamont utilises four main starch-based plastic compounds that vary in its additives for the desired purpose. Collectively trademarked as Mater-Bi, these biodegradable plastics are used to manufacture a whole range of products such as garbage bags, diapers and organic food packaging (Bastioli, C. 1998). Starch-based polymers also have many surgical applications because of their porous nature and biocompatibility. This material has proven particularly useful in support braces for tissue-bone regeneration because it allows blood vessel proliferation during the natural healing process (Salgado, A. J., Coutinho, O. P. & Reis, R. L. 2004). In addition, they do not inhibit cell growth and did not produce severe inflammatory responses when tested on rats; this furthers their potential for further applications (Marques, A. P., Reis, R. L. and Hunt, J. A., 2005). Are Starch-Based Polymers Truly Degradable? Strictly speaking, the term degradable plastics is misleading as it implies that normal petroleum-based plastics are not biodegradable, which is untrue. For practical reasons, petroleum-based plastics are regarded as non-biodegradable because they are extremely durable and take centuries to breakdown. Thus degradable plastics, either biodegradable or photodegradable, are plastics that have been engineered to rapidly decompose in the natural environment. ...read more.

Conclusion

Therefore, large scale implementation is difficult (Griffin, G. J. L. 1976). Conclusions Starch-based polymers are a promising alternative to the current petroleum-based, non-biodegradable plastics. Over the past fifty years, a lot of research has been generated to find a suitable alternative to oil-based plastics but much is still unknown. Issues such as the byproducts of the biodegradation process and their exact chemical composition have yet to be formally studied. Although small and seemingly insignificant, these byproducts could be poisonous and without proper identification, these products could contaminate water supplies and have a major affect on the environment they had originally been invented to protect. Unfortunately, economic pressures prevent money from being pumped into the development of biodegradable forms of plastic as companies would have to recuperate the millions already invested into the research and development of these plastics. Although biodegradable polymers are valuable in specialty areas such as healthcare and agriculture, large scale commercial implementation of biodegradable plastics into already stable oil-based plastic markets, such as packaging, is still under development as until prices become more idealistic. It might still be a long time before biodegradable, starch-based plastics replace petroleum-based plastics in the market. ...read more.

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