The copolymerization of $varepsilon$-caprolactam(CL) and PPG-diamine has been performed using various activators such as tolylene dicarbamoyl dicaprolactam(TDC), hexamethylene dicarbamoyl dicaprolactam(HDC), and 1,3-bis(2-isocyanato-2-propyl) benzene/CL adduct(IDC) and sodium caprolactamate as a catalyst. The overall rate of polymerization of CL has been studied by fitting the experimental temperature rise with a polymerization kinetic equation involving the polymerization exotherm, polymerization-induced crystallization exotherm, and the heat loss due to nonideal adiabatic condition in the experimental situation. It was observed that for identical concentration of activator used in the presence of the impact modifier(PPG-diamine), HDC showed the fastest rate of polymerization and TDC showed the slowest one. The slowest activator TDC showed the highest yield of copolymerization, whereas IDC showed the lowest yield of copolymerization.