Copolymerization and Copolymers of Acrylonitrile with Some Brominated Phenylmaleimides

Acrylonitrile (AN) was copolymerized with N-(4-bromophenyl)-maleimide (BPMI) or N-(2,4,6-tribromophenyl)maleimide (TBPMI) in toluene solution using azobisisobutyronitrile as the free radical initiator. The monomer reactivity ratios were found to be for BPMI (M1)-AN (M2), r1=0.44 ± 0.082 and r2 = 1.82 ± 0.125, and for TBPMI (M1)-AN (M2), r1 = 0.053 ± 0.051 and r2 = 4.71 ± 0.275. The e and Q values were also calculated. The course of copolymerization to high conversion is characterized by a remarkable decrease of the initial reaction rate as well as of overall conversion as the fraction of brominated monomer in the monomer mixture is increased. However, these values are somewhat higher when BPMI is used as a comonomer. The resulting copolymers show a higher thermal stability than that of polyacrylonitrile, and the glass transition temperature increases markedly with increasing BPMI or TBPMI content.