Copolymerization of ethyl methacrylate with N-(3- or 4-halogenphenyl)maleimides: The monomer reactivity ratios

The copolymerization of ethyl methacrylate [I] with N-(3-chlorophenyl)maleimide [II], N-(4-chlorophenyl)maleimide [III], N-(3-bromophenyl)maleimide [IV], and N-(4-bromophenyl)maleimide [V] was carried out in benzene, using α,α′-azobisisobutyronitryle as an initiator at 60°C. The copolymer compositions were estimated by elemental analysis. The monomer reactivity ratios of [I] (r1) with [II], [III], [IV], and [V] (r2) were determined by the Fineman–Ross and Kelen–Tüdös methods, and recalculated using the nonlinear minimization algorithm based on Mayo–Lewis's method (RREVM). The Alfrey–Price copolymerization parameters Q and e for N-(3- or 4-halogenphenyl)maleimides were also calculated. The kind of halogen atom (Br- or Cl-) and its position in the phenyl ring of maleimide on the values of reactivity ratios r1 and r2 are discussed.