Superior Impact Toughness and Excellent Storage Modulus of Poly(lactic acid) Foams Reinforced by Shish-Kebab Nanoporous Structure

Poly(lactic acid) (PLA) foams, with the combination of shish-kebab and spherulite nanoporous structure in skin and core layer respectively, was prepared using a novel technique comprising loop oscillating push–pull molding (LOPPM) and supercritical carbon dioxide low-temperature foaming process (SC−CO2LTFP). The foams present superior impact toughness which is 6-fold higher than that of neat PLA, and no significant decrease was observed for the storage modulus. Moreover, SC−CO2LTFP at soaking temperature ranging from 110 to 150 °C were performed to determine the evolution of pore morphology. The ultratough and supermoduli are unprecedented for PLA, and are in great need for broader applications.