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Keywords:

  • core–shell particles;
  • internal structure;
  • grafting degree;
  • brittle–ductile transition temperature

Abstract

Methyl methacrylate–butadiene–styrene (MBS) core–shell particles were prepared by grafting styrene and methyl methacrylate onto polybutadiene seeds via emulsion polymerization. All the MBS particles were designed with the same chemical composition, similar grafting degree but different internal structures. The difference in internal structure was realized by controlling the ratio of ‘external grafting’ and ‘internal grafting’ of styrene. The work focused on the influence of the internal structure of MBS core–shell particles on the properties of poly(vinyl chloride)/MBS blends. From transmission electron microscopy, three different internal structures were observed: rare sub-inclusions, a large number of small sub-inclusions and large sub-inclusions. The results of dynamic mechanical analysis illustrated that the different internal structures greatly affected the glass transition temperature Tg of the rubber phase and the storage modulus of the core–shell particles. The notched Izod impact test results showed that the MBS with large sub-inclusions had the lowest brittle–ductile transition temperature, while the transparency test revealed that the presence of sub-inclusions in the rubbery phase reduced the transparency of the blend. Copyright © 2012 Society of Chemical Industry