Acrylonitrile-Styrene-Acrylate Resin with Superior Low Temperature Toughness by Preparing a Core–Shell Phase Morphology of Two Rubbers through the Effect of Interfacial Tensions

The phase morphology of acrylate rubber (PBA) in acrylonitrile-styrene-acrylate (ASA) copolymer and silicone rubber was designed to be a core–shell structure in the acrylonitrile-styrene (AS) resin matrix by taking advantage of their interfacial tension differences during blending with a twin-screw extruder. Prior to this, in order to enhance the compatibility with silicone in AS resin, we grafted AS to the silicone rubber nanoparticles, synthesizing a silicone-g-AS (SiAS) copolymer. The selective extraction test and SEM images verified the formation of the core–shell structure. This distinctive phase morphology, featuring a silicone core and an acrylate shell in SiAS/ASA/AS ternary blends, significantly improves their impact strength at −30 °C, 0 °C, and 25 °C. Notably, the impact strength of SiAS/ASA/AS (Si9A21) at −30 °C is five times that of the commercial product (Si0A30). The SEM images of the impact section indicate that introducing ductile silicone rubber into the interior of acrylate rubber microparticles can increase and refine the cavitation of the rubber layer upon impact. The TGA results indicate that SiAS considerably enhances the heat resistance of the ternary blends. The tensile and flexural properties of the SiAS/ASA/AS ternary blends demonstrate that the ternary blends do not lose their intrinsic physical properties.