With DMF as solvent

the kinetics of copolymerization systems of four N-p-substituted phenyl maleimides with styrene in solution was systematically studied by means of dilatometry.The polymerization rate equation of N-phenyl maleimide with styrene is Rp=k[I]1/2[M].The polymerization rate of other N-p-substituted phenyl maleimides with styrene were also a linear function of monomer concentration.The overall apparent copolymerization rate constants and apparent copolymerization activity energy of the four N-p-substituted phenyl maleimides with styrene were determined

which confirmed that the polymerization activity of the four N-p-substituted phenyl maleimides with styrene decreases in an order as follows:N-p-chlorophenyl maleimide

N-phenyl maleimide

N-p-tolylphenyl maleimide and N-p-tolyloxyphenyl maleimide.The apparent copolymerization activity energy of N-p-chlorophenyl maleimide with styrene was the smallest because the polarization difference between N-p-chlorophenyl maleimide and styrene was the biggest.The result was in accordence with the theory of CTC complex

which provided the evidence of the existence of CTC complex.