Stereocomplexed polylactides (Neo-PLA) as high-performance bio-based polymers: their formation, properties, and application

Polymeric materials prepared from renewable natural resources are now being accepted as bio-based polymers, because they are superior to the conventional petroleum-based polymers in reducing the emission of carbon dioxide. Among them, poly(L-lactide) (PLLA) prepared by fermentation and polymerization is paid an immediate attention. Although PLLA exhibits a broad range of physico-chemical properties, its thermal and mechanical properties are somewhat poorer for use as ordinary structural materials. For improving these inferior properties, a stereocomplex form consisting of PLLA and its enantiomer poly(D-lactide) (PDLA) has high potential because of showing high melting nature (230 degrees C). It can be formed by simple polymer blend of PLLA and PDLA or more easily with stereoblock polylactides (sb-PLA) which are PLLA/PDLA block copolymers. These novel PLA polymers, named Neo-PLA, can provide a wide range of properties that have never be attained with single PLLA. Neo-PLA retains sustainability or bio-based nature, because both monomers L- and D-lactic acids are manufactured from starch by fermentation. (c) 2006 Society of Chemical Industry.