The influence of the arrangement of styrene in methyl methacrylate/butadiene/styrene on the properties of PMMA/SAN/MBS blends

A series of methyl methacrylate-butadiene-styrene (MBS) core–shell impact modifiers were prepared by grafting styrene (St) and methyl methacrylate (MMA) onto polybutadiene (PB) or styrene-butadiene rubber (SBR) seed latex in emulsion polymerization. All the MBS modifiers were designed to have the same total chemical composition, and Bd/St/MMA equaled 39/31/30, which was a prerequisite for producing transparent blends with poly(MMA)/styrene-acrylonitrile (PMMA/SAN) matrix copolymers. Under this composition, different ways of arrangement for styrene in MBS led to the different structure of MBS modifier. The concentration of PB or SBR rubber of MBS in PMMA/SAN/MBS blends was kept at a constant value of 15 wt.%. The effects of arrangement of St in MBS on the mechanical and optical properties of PMMA/SAN/MBS blends were investigated. The results indicated that Izod impact strength of PMMMA/SAN/MBS blend with the amount of St grafted on core in MBS was higher than that of blend with the amount of St copolymerized with Bd in core of MBS, while the transparency of blend is opposite. From transmission electron microscopy, it was found that the arrangement of St in MBS influenced the dispersion of blend, which led to different toughness. Copyright © 2013 John Wiley & Sons, Ltd.