Effect of octa(epoxycyclohexyl) POSS on thermal, rheology property, and foaming behavior of PLA composites

Foams of poly(lactic acid) (PLA)/octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (ePOSS) composite were prepared by melt-mixing and solid-state foaming methods. A systematic and accurate method was applied to evaluate the effects of epoxy-based POSS on the structure of dispersion, thermal behavior, and rheological properties of PLA composites. The application of secondary electron-electron back-scattered diffraction technique was used to observe the cellular micromorphology and micro-phase dispersion in composite foams, simultaneously. The results indicated that secondary dispersion of POSS aggregates occurred in foaming process. The enhanced melt elasticity, dispersity of POSS, and crystallization morphology of PLA/POSS composite had a significant effect on the controlling foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA/POSS composite foam with high expansion ratio was obtained with a proper content of POSS in the composites. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46399.