Copolymerization of N-phenylmaleimide with styrene by rare earth coordination catalyst

The copolymerization of N-phenylmaleimide (NPMI) with styrene (St) was studied with a rare earth coordination catalyst Nd(naph)3–AlEt3 in toluene at 50 °C. The compositions of the two monomers in copolymers were close to 1:1 even at a high monomer conversion of about 60%, and did not change as the NPMI feed mole fraction varied from 10% to 90%. The copolymer was characterized by 13C nuclear magnetic resonance spectroscopy, showing that the copolymer possessed a nearly alternating structure. The thermal properties of the copolymers were also investigated. It was presumed that a charge transfer complex of NPMI and St participated in the polymerization process.