Supercritical fluid technology parameters affecting size and behavior of stereocomplex polylactide particles and their composites

Polylactide (PLA) is a eco-friendly and biodegradable material that can be synthesized from renewable resources. PLA features poly(d-lactic acid) (PDLA) and poly(l-lactic acid) (PLLA) enantiomers. Supercritical fluid (SCF) technology is a very promising method for the stereocomplexation between PDLA and PLLA enantiomers. This study acquires stereocomplex (sc-)PLA particles with diverse sizes and behaviors by controlling the experimental conditions. Various parameters including polymer concentration, reaction temperature, stirring speed, pressure reducing speed, and final temperature were controlled to adjust size and behavior of sc-PLA particles. Additionally, we analyzed the effect of subsequent processing following SCF (such as homogenization, mechanical stirring, and sonication) on the size and morphological behavior of sc-PLA particles. Finally, the mechanical strengths of different PLA composites featuring different sc-PLA filler sizes were determined. The mechanical strength of PLA composites was significantly improved when using smaller filler sizes. POLYM. ENG. SCI., 58:1193-1200, 2018. (c) 2017 Society of Plastics Engineers