ACRYLIC THERMOPLASTIC ELASTOMERS AND COMB-SHAPED POLY(METHYL METHACRYLATE) VIA THE MACROMONOMER TECHNIQUE

Comb-shaped poly(methyl methacrylate) (PMMA) and poly(butyl acrylate) (PnBuA) grafted with PMMA were prepared by radical copolymerization of omega-methacryloyl-PMMA with MMA and nBuA, respectively. The comb-sha ped PMMA is characterized with respect to radius of gyration by using gel permeation chromatography equipped with a multi-angle laser light scattering detector. The radical copolymerization of the macromonomer with nBuA in toluene follows complex kinetics. The dependence of the r elative reactivity of the macromonomer on absolute concentration and o n the ratio of comonomers may be explained by preferential solvation o f comonomers by segments of their own kind (''bootstrap effect'') or e ven micelle formation. However, there is no clear evidence for the for mation of micelles in toluene. In contrast, NMR studies show micelle f ormation in the preferential solvent dimethyl sulfoxide. The graft cop olymers are transparent thermoplastic elastomers. Phase separation is demonstrated by differential scanning calorimetry and morphological st udies.