Toughening performance of ASA core-shell graft copolymers constructed with various crosslinking agents on SAN resins

In this study, poly(butyl acrylate) (PBA) seed latex was prepared through seed emulsion polymerization using five crosslinking agents: dicyclopentenyl acrylate (DCPA), N, N’-methylenebisacrylamide (MBA), ethylene glycol dimethacrylate (EGDMA), 2-(Dimethylamino)ethyl methacrylate (DMAEMA, abbreviated as DMA), and pentaerythritol tetraacrylate (PETA). After grafting, a series of acrylate-styrene-acrylonitrile (ASA) graft polymers were synthesized for toughening SAN Poly(styrene-co-acrylonitrile) resin. The results show that among the various types of crosslinking agents, DMA gives ASA grafted powders the most uniform particle size distribution and the highest grafting rate (34.6%), which is attributed to the electron-donating effect of its tertiary amine group. In the SAN/ASA (35/25) blend system, ASA particles crosslinked with DMA increased the impact strength to 21.7 kJ/m 2 , more than six times higher than that of pure SAN, with an elongation at break of 28.44%, while the Young’s modulus remained at 2481.6 MPa. The impact fracture surface was rough with evenly distributed pores, demonstrating excellent toughness. These findings reveal that the chemical structure of crosslinking agents not only governs the morphology and crosslinking density of the PBA core but also profoundly influences the energy dissipation mechanisms of the ASA/SAN blend system. This study provides a theoretical foundation and experimental evidence for the rational design of high-performance ASA toughening systems.