Reactivity ratios and sequence distribution of styrene-acrylonitrile copolymers synthesized in microemulsion medium

The reactivity ratios of styrene and acrylonitrile in ternary oil-in-water anionic microemulsions were observed to be very much different than those i n bulk, solution, emulsion and cationic microemulsion media. The results ar e discussed in terms of partitioning of partially water soluble monomers in the aqueous phase and monomer droplets. The behavior of polymerization was observed to follow a terminal model rather than the penultimate model in a microemulsion medium. Sequence distribution in copolymers was calculated f rom reactivity ratios using the Alfrey-Mayo model and was observed to be in good agreement with that calculated from C-13-NMR studies. A good agreemen t was observed in glass transition temperatures of copolymers and those cal culated from C-13-NMR. (C) 2000 Elsevier Science Ltd. All rights reserved.