Super-Tough Poly(lactic Acid)-Based Thermoplastic Vulcanizate Based on Selective Dispersion and In Situ Compatibilization of Commercial Reinforcing Fillers and Its Application in Three-Dimensional Printing

Blending with elastomers is a commonly used method to improve the toughness of poly(lactic acid) (PLA). However, the poor compatibility between polar PLA and the nonpolar elastomer results in a limited improvement of the toughness. In this work, we report a simple but effective strategy to improve the compatibility between PLA and natural rubber (NR) and manufacture super-tough PLA-based thermoplastic vulcanizate (TPV). We choose the widely used reinforcing filler SiO 2 nanoparticles as the compatibilizer, whose modification using 3-(trimethoxysilyl)propyl methacrylate (KH570) is synchronized with the dynamic vulcanization. Simultaneously, the modified SiO 2 nanoparticles migrate from the NR phase to the PLA/NR interface due to the interfacial tension. The modified SiO 2 nanoparticles located at the interface entangle with the NR chains on the one hand and graft with the PLA chain on the other hand, acting as a “bridge” to improve the interfacial compatibility of the two phases. While only adding a small amount of filler, 20 phr SiO 2 nanoparticles in NR and 7 phr modifier in SiO 2, the impact strength of the PLA/NR (80/20) TPV increases to 95.96 kJ/m 2 (without fracture), which is 38-fold than pure PLA. Even in a low temperature of −30 °C, the impact strength is still 7.93 kJ/m 2 . Finally, the co-continuous structure and the excellent toughness with a small amount of toughener make the TPV have great potential for application in the 3D printing field (processing speed of 110 m/min, over 100 times bend after immersion in hot water).