Core-Shell Structure Acrylonitrile-Styrene-Acrylate Particles with Different Acrylonitrile Contents Improved Toughness of Poly(styrene-co-acrylonitrile) Resins

Abstract

Abstract Herein, core-shell structured grafted copolymer particles of poly(butyl acrylate) grafted polystyrene acrylonitrile (ASA) with different contents of acrylonitrile (AN) were prepared by emulsion graft polymerization. ASA resins were then obtained by melt blending of ASA graft copolymers with SAN (w/w, AN/St, 25/75) resins. This paper investigates the effect of acrylonitrile content in ASA graft copolymers on the mechanical properties of ASA resins. The particle size distribution, composition of ASA, cross-section morphology, and compatibility of the material were characterized by dynamic light scattering (DLS), nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). The results revealed the highest notched impact strength of ASA resin reaching up to 277.49 J/m at AN content of grafted SAN of 21%, equivalent to an 80% increase when compared to 25% AN content. The lap shear adhesion tests revealed excellent interfacial adhesion between the ASA particles and SAN matrix owing to the difference in AN. This significantly enhanced the toughness of the ASA resin. Additionally, the ASA particles displayed the widest particle size distribution. The synergistic toughening of small and large rubber particles also enhanced the impact resistance of ASA resin to a certain extent. Therefore, the excellent interfacial adhesion between ASA graft copolymer and SAN matrix and the synergistic toughening of large rubber particles together promote the toughness of ASA resin.