Synthesis of poly(dimethylsiloxane) and poly(butadiene) composite particles and the properties of their grafted polymer particles

Micro separated composite polymer particles comprising of poly(dimethylsiloxane) (PDMS) and poly(butadiene) (PB) were prepared by an emulsifier-free seeded emulsion polymerization of butadiene with a radical initiator in the presence of a PDMS latex. The following three factors controlled the morphology of the particles: (i) cross-linking degree of PDMS; (ii) cross-linking degree of PB; and (iii) source of polymerization initiator. By decreasing the cross-linking degree of PDMS or PB, we obtain segregated PB from PDMS. An initiation system consisting of tert-butyl peroxylaurate and ferrous sulfate gave the hemispherical morphology in contrast to the core shell for potassium persulfate. Styrene and acrylonitrile were able to graft onto the PB phase of the particles with high efficiency. The corrections between the morphology of the composite polymer particles and the practical properties of poly(styrene-co-acrylonitrile)-modified graft polymers were also discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.