COPOLYMERIZATION AND COPOLYMERS OF ACRYLONITRILE WITH SOME BROMINATEDPHENYLMALEIMIDES

Acrylonitrile (AN) was copolymerized with N-(4-bromophenyl)-maleimide (BPMI) or N-(2,4,6-tribromophenyl)maleimide (TBPMI) in toluene solutio n using azobisisobutyronitrile as the free radical initiator. The mono mer reactivity ratios were found to be for BPMI (M1)-AN (M2), r1 = 0.4 4 +/- 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 chara cterized 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 high er when BPMI is used as a comonomer. The resulting copolymers show a h igher thermal stability than that of polyacrylonitrile, and the glass transition temperature increases markedly with increasing BPMI or TBPM I content.