Facile Preparation of Supertoughened Polylactide-Based Thermoplastic Vulcanizates without Sacrificing the Stiffness Based on the Selective Distribution of Silica

Blending with elastomers is one of the most effective strategies for toughening polylactide (PLA) but faces the challenge of a sharp decline in stiffness. In this work, PLA/epoxidized natural rubber (ENR)/silica (SiO 2 ) thermoplastic vulcanizates (TPVs) with balanced stiffness–toughness were designed via dynamic vulcanization. The PLA/ENR/SiO 2 TPVs exhibited a cocontinuous structure in which SiO 2 nanoparticles were regulated to selectively distribute in the ENR phase. SiO 2 nanoparticles enhanced the mechanical strength and thickness of ENR network, resulting in efficient toughening of PLA without sacrificing its stiffness. With 20 phr SiO 2, the TPVs showed an excellent cryogenic impact toughness of 54.5 kJ/m 2 at 0 °C, which was 8.3 times that of the PLA/ENR blend. Meanwhile, incorporation of SiO 2 made the TPVs sustain a high retention rate of the tensile strength (98.2%). The synergistic toughening mechanism of SiO 2 nanoparticles and ENR was investigated via a series of testing methods, proposing a feasible approach to fabricate high-performance TPVs.