Biopolymers: Biodegradable Alternatives to Traditional Plastics

Abstract

A variety of biologically derived polymers (termed "bio-based polymers" or "biopolymers") have been examined for replacement of petrochemically derived polymers in many applications. In general, these polymers have either a structural or a nutritional role in the organisms that synthesize them. As biopolymers for our use, they have been removed from their biocatalyst organism and purified to assess their molecular properties. Biopolymers have a variety of structural characteristics that make them useful for different applications. In many cases, such as medical applications, biocompatibility is required of polymers; however, mechanical strength, flexibility, toughness, structural stability, and biodegradability may also be required. In this chapter, animal-based polymers (collagen, silk), plant-based polymers (cellulose, starch), and microbe-derived polymers (polyhydroxyalkanoate, cellulose) are examined in terms of their primary chemical structure, functions, and application as bio-based alternatives to petroleum-based polymers.