An overview on biodegradable polymer

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An Overview On Biodegradable Polymer’s Firdoous.A.Mir, Dr. P.Asokan Building Material Development Group Advanced Materials & Processes Research Institute, C.S.I.R. Bhopal -462026 * Email: asokanp3@yahoo.co.in Conclusion Introduction Acknowledgement - The authors are grateful to the Director, A.M.P.R.I., Bhopal for encouragement of the research work and kind Permission to publish this paper. Biodegradable polymers are designed to degrade upon disposal by the action of living organisms. Biodegradable means capable of undergoing decomposition into carbon dioxide, methane water, inorganic compounds or biomass in which the predominant mechanisms is the enzymatic action of micro-organisms that can be measured by standard tests, over a specific period of time, reflecting available disposal conditions. There are different media (liquid, inert or compost medium) to analyze biodegradability. Review of work done Naturally occurring biopolymers are derived from four broad feedstock areas (Tharanathan 2003). Animal sources. Marine sources. Microbial biopolymer. Agricultural feedstocks. Biopolymers that may be employed in packaging continue to receive more attention than those designated for any other application (Chau et al.1996, Bastioli 1998). BASF, a world leader in the chemical and plastic industry, is working on development of biodegradable plastics based upon polyester and starch (Fomin et al. 2001). Ecoflex is a fully biodegradable plastic material that was introduced to consumers by BASF in 2001. It is resistant to water and grease, making it appropriate for use as a hygienic disposable wrapping, fit to decompose in normal composting systems. Consequently, Ecoflex has found a number of applications as a packaging wrap. Biodegradable loose-fill packaging materials may be developed from renewable biopolymers such as starch ( Guan and Hanna 2002). Medical world is constantly changing, and consequently the materials employed by it also see recurrent adjustments. Researchers working in tissue engineering are attempting to develop organs from polymeric materials, which are fit for transplantation into humans (Mukhopadhyay 2002). Automotive sector is responding to societal and governmental demands for environmental responsibility. Substituted natural fibers for glass fibres as reinforcement materials in plastic parts of automobiles and commercial vehicles (Lammers and Kromer 2002). Engineers are attempting to integrate environmental considerations directly into material selection processes, in order to respond to an increased awareness of the need to protect the environment (Thurston et al. 1994). United States, currently less than 10% of plastic products are recycled at the end of their useful life (Chiellini et al. 2001). A complacent attitude regarding recycling processes ignores the fact that advanced infrastructure is needed to properly house recycling. In underdeveloped countries plastics are almost completely recycled, as the return on investment is positive in their economic situation. This appears to be positive at the onset, but the open systems by which the plastics are recycled allow the emission of toxic gases at crucial levels (Mulder 1998). Researchers worldwide are interested in the area of biopolymer development. The German government has stringent regulations in place regarding acceptable emission levels. There are a seemingly limitless number of areas where biodegradable polymer materials may find use. The sectors of agriculture, automotives, medicine, and packaging all require environmentally friendly polymers. Because the level of biodegradation may be tailored to specific needs, each industry is able to create its own ideal material. The various modes of biodegradation are also a key advantage of such materials, because disposal methods may be tailored to industry specifications. Classification Biodegradable polymers Biomass products from agro resources -Agropolymers From micro organisms (obtained by extraction) Starch, wheat, potatoes, maize Lignocellulose products : Wood From biotechnology Polylactides PLA Lignocellulose products : Wood Others: Pectins,gum PHA PHA PHB PCL PEA PBAT Polysachrides Protiens,lipids Animals:casine, Gelatin Plant: Zelt, soya Why We Prefer Synthetic polymers than natural one Ones Tailor-able properties Predictable lot-to-lot uniformity Free from concerns of immunogenicity Reliable source of raw materials Degradation Chemical means Physical means (A)Bulk-eroding system PLA,PGA,PLGA, PCL (B) Surface-eroding system C changes occurs in polymers which includes cleavage of covalent bonds, hydrolysis, ionization or protonation either along the back bone or side chains of polymers. Chemical degradation leads to the change in molecular weight or solubility of polymer.