Characterization of Biodegradable Plastics

Abstract Polymers deteriorate by a number of mechanisms. In the lifetime of a polymer, deterioration may proceed gradually or rapidly. During processing, a polymer is melted and formed to a desired shape; it undergoes some deterioration due to the extreme temperature and mechanical stress. For example, polymer chains may rupture at the molecular level as a result of high shear stress encountered during processing. When mechanical stress contributes to failure or deterioration, the process is termed mechanical degradation or stress-induced degradation. When the thermal stress contributes to failure or deterioration, the process is termed thermal degradation. The degree to which a polymer undergoes deterioration depends on the thermal and mechanical stresses the material experiences during processing. Although the deterioration process of polymers is prominent under extreme conditions of temperature and pressure, in general, these materials undergo mild deterioration under ambient conditions.