SYNTHESIS OF POLYLACTIDE-GRAFT-MALEIC ANHYDRIDE VIA FREE RADICAL INITIATION IN SUPERCRITICAL CARBON DIOXIDE

摘要

One of the most popular bio-based polymers on the market today is polylactide (PLA). Although PLA is bio-based, biodegradable, produced on a large scale, and able to be processed by traditional polymer processing equipment, its widespread use is limited by its relatively poor mechanical properties. PLA possesses a high tensile modulus, but low elongation and toughness. It is an inherently brittle material and therefore a poor choice for flexible packaging applications in its virgin form. PLA can be melt blended with more flexible polymers to increase its suitability for a wider range of applications, but due to their high molecular weight and viscosity, polymers are rarely miscible with each other. Immiscible polymer blends cause premature separation of polymeric phases, discontinuity of mechanical and thermal properties, and shortened service life. Graft copolymers can serve as compatibilizers between immiscible polymer blends to improve their miscibility and subsequent mechanical properties.