Biobased and biodegradable plastic products based on annually renewable agricultural and biomass feedstocks can form the basis for a portfolio of sustainable products that are environmentally preferable, green alternatives to current materials based exclusively on petroleum feedstocks. The need for products to be fully biodegradable in a defined time frame in the selected disposal infrastructure as opposed to degradable or partially biodegradable will be reviewed.

Bioplastics from renewable resources offer the intrinsic value proposition of a carbon neutral footprint and in complete harmony with the natural biological carbon cycle. This presentation explains the fundamental principles on which this is based. To be classified as “bio” or biobased, the bioplastic or bioproduct must be organic and contain recently fixed (new) carbon from annually renewable resources.

Polyhydroxyalkanoates (PHA) are microbial polyesters offering the advantages of biodegradability and biocompatibility over traditional petroleum based thermoplastics with almost similar properties. However, their highly crystalline nature, excessive brittleness and high price have prevented them from being a commercial success. Functionalization of PHA by maleation and their composites with natural fibers/ clay nano-particles can help overcome these shortcomings. Poly(3-hydroxybutyrate) (PHB), one of the most common PHA is chosen for this study.

Polylactide (PLA) biopolymers are currently enjoying strong commercial interest as sustainable alternatives to commodity petroleum-based plastics in a wide variety of thermoformed packaging applications. Typically, the properties of unmodified PLA resins are sufficient to meet the performance requirements of these applications, providing the temperature-performance requirement remains less than about 50°C.

Completely revised and updated, the second edition considers those polymers in which a highly nonlinear response of a smart polymer to small changes in the external medium is of critical importance for the successful functioning of the system. The systems discussed are based on soluble/insoluble transition of smart polymers in aqueous solution, on conformational transitions of the macromolecules physically attached or chemically grafted to a surface and on the shrinking/swelling of covalently cross-linked networks of macromolecules, i.e. smart hydrogels.

Mirel™ poly(hydroxy butanoic acid), or PHB copolymers, and their products are known to biodegrade in soil and compost sites and in freshwater and seawater environments. Because they biodegrade in soil, PHB copolymers are very well suited for agricultural mulch film applications. Vegetable-crop growth with PHB copolymer mulch films in various environments has been shown to be considerably better than bare-ground crop growth and similar to crop growth with polyethylene mulch films.