Compositions and methods for manufacturing polymers are disclosed. Compositions include novel plastics, including films and shaped forms comprising polymer matrices that are biologically compatible and biodegradable. Such plastics may comprise polymers derived from natural sources. Further, such plastics are useful in biological systems for wound repair, implants, stents, drug encapsulation and delivery, and other applications. The disclosed methods comprise mild manufacturing processes such that various additives, such as biologically active proteins, sugars, lipids, and the like may be incorporated into the polymer matrix without subsequent loss of bioactivity during processing. Additionally, methods of manufacture for controlling mechanical properties, such as elasticity, pliancy, and the porosity of such plastics are disclosed.