Preparation of core–shell acrylonitrile-styrene-acrylate impact modifier particles through seeded emulsion polymerization

The design and preparation of conventional impact modifiers with core-shell structure have attracted the attention of researchers. Herein, acrylonitrile-styrene-acrylate (ASA) core-shell impact modifier with different core contents was prepared through two-stage seeded emulsion polymerization. In the first stage, partially crosslinked poly (butyl acrylate) (PBA) rubber, as the core, was synthesized and then, styrene and acrylonitrile comonomers were grafted onto the surface of PBA seeds to conform crosslinked poly(styrene-acrylonitrile) (SAN) shell. Chemical structure of PBA and grafting of SAN onto the PBA surface was verified. Spherical morphology of the prepared particles and particles size, which layed within the range of 170-200 nm, were approved by SEM and DLS analyses. The observed unimodal particle size distribution for ASA particles refered to the absence of secondary particles during seeded emulsion polymerization. Moreover, core-shell morphology of the prepared ASA particles was approved by TEM analysis.