Department of Textile Technology, Indian Institute of Technology, Delhi, New Delhi-110 016 Acrylonitrile (AN) was copolymerized with ((2-methacryloyloxy)ethoxy]trimethylsilane (2-MAETMS) and (2methacryloyloxy]propoxy] trimethylsilane (2-MAPTMS) in dimethylformamide and dimethylsulfoxide at temperatures between 50º and 70° using azoblslsobutyronitrile(AmN) as Initiator. The copolymer composition was determlued by silicon atimatloa and reactivity ratios were calculated by the Kelen-Tudos method. In both tbe systems, r1(AN) and r2(2-MAETMS/2-MAPTMS) are higher In DMF compared to the values in DMSO. Arrhenius parameters were derived for AN-2-MAETMS system. Tbe difterence between the activation energies (E11-E12) favour self-propagation for the acrylonitrile radical, whereas A11/A12 favours crosspropagation. In case of 2-MAETMS radical, E22-E21 favoun cross-propagatlou but A22/ A21 favours self-propagation. The Influence of the comonomers on some of the basic properties of copolymers like solubility, Intrinsic viscosity, softening and glass transitions have also been studied.