Polylactic Acid Based Blends and Biocomposites with Improved Performance

摘要

In an effort to improve the toughness of PLA, multiphase blends of PLA,rnethylene-methyl acrylate-glycidyl methacrylate (EMAGMA) terpolymer and arnpartially biobased thermoplastic copolyester elastomer, Hytrel (HYT) were fabricatedrnthrough reactive melt blending. High impact strength with non break behavior wasrnachieved at an optimized blending ratio of 70 wt% PLA, 20 wt% EMAGMA and 10rnwt% HYT. A unique morphological structure with partial encapsulation of GMA andrnHYT minor phases was observed for the PLA/GMA/HYT (70/20/10) blend revealingrnthe importance of particular blend morphology and composition in enhancing therntoughness. In order to achieve concurrent improvements in impact strength and heatrndeflection temperature (HDT) of PLA, the super-toughened blend was combined withrnnatural fibers and nucleating agents to fabricate PLA biocomposites. Mechanical andrnthermal properties assessment revealed a 4 fold increase in impact strength comparedrnto neat PLA and the HDT of PLA biocomposites increased to 88℃ from 55℃ notedrnfor neat PLA and PLA blends. With the addition of 1 wt% Lak-301 as nucleatingrnagent at mold temperature of 110℃ PLA biocomposites exhibited dramatic reductionrnin crystallization half time to 1.3 min with crystallinity content of 42%.