Design of PLA/ENR thermoplastic vulcanizates with balanced stiffness-toughness based on rubber reinforcement and selective distribution of modified silica

Elastomer-toughened PLA has incubated plenty outstanding achievements. Principally, increasing elastomer content will immolate vast rigidity in exchange for toughness. In this work, silane coupler KH550-treated SiO2 and ENR were used to synergistically enhance and toughen PLA via dynamic vulcanization. It is found that the PLA/ENR/SiO2 TPV with balanced stiffness and toughness exhibited a bi-continuous phase structure. Thereinto, the hydrophobic SiO2 nanoparticles were regulated to uniformly disperse in the ENR phase, which played an essential role in reinforcing the rubber and bracing the symmetrical rubber network, so as to toughen the PLA with retaining high stiffness at an acceptable plastic-to-rubber ratio. By incorporating nano-SiO2 modified with 10 phr KH550, the TPV could obtain an impact strength of 23.7 kJ/m(2) at 0 degrees C while maintain a tensile strength of 42.1 MPa, which were 1.62-fold and 1.03-fold of those before modification, respectively. The synergistic enhancing and toughening mechanism of nano-SiO2 and ENR was revealed through a series of test and analysis, which furnished a succinct and effective proposition of fabricating high-performance PLA materials.