Research On The Effects Of SAN Free Chains In ABS Modifiers

For the ABS core-shell modifier, because the unsaturation double bond in PB rubber particle, which could be reacted with SAN copolymer, then grafted on the PB surface.However, in the synthetic process, grafting reaction and copolymerization competed with each other, which led to the SAN could not be grafted on the rubber particle. The part of SAN dispersed in the shell, called free chain. And in the studies about ABS modifier, the studies for the free chain were rare.In this study, acrylonitrile butadiene styrene(ABS) core-shell modifiers of different core-shell ratios and the co-polymer of ABS and glycidyl methacrylate(ABS-co-GMA)were prepared by seeds emulsion polymerization. Then the SAN free chains in the modifiers were separated out by ultra-centrifugation. The modifiers were blended PBT resin respectively to investigate the the influence of the SAN free chains on the properties of the blends.The results showed that the free chains in the three kinds of modifiers declined to show little effect on the compatibility, elastic modulus and tensile strength of the blend.For the ABS modifier in which core-shell ratio was 40/60, the existence of SAN free chains reduced the impact strength and elongation at break. The free chains showed negative influence on the impact strength of the blends. However, for the 60/40 ABS modifier, the existence of SAN free chains increased the elongation at break. In other word,the free chains played a positive role in the blends. Moreover, in the ABS-co-GMA modifier, the free chains played a positive role in the blends of PBT and modifiers.