Showing papers by "Maher Z. Elsabee published in 1987"

Copolymerization of Methyl Methacrylate with N-Phenylmaleimide in Different Solvents

Abstract: The copolymerization of methyl methacrylate (MMA) and N-phenyl-maleimide (NPMI) in various solvents has been studied. It has beerr shown that monomer-monomer interaction exists and leads to the formation of a weak charge-transfer complex (CTC). The CTC concentration is found to depend on the type of solvent, and its equilibrium constant depends on the dielectric constant of the solvent and increases in the order DMSO < chloroform < benzene < CC14. NMR and dipole moment measurements have been used to investigate interaction between the monomers. The monomer reactivity ratios are found to vary appreciably with the type of solvent. The data obtained indicate that changes in the reactivity ratios are due to monomer solvation or to the solvent effect on the propagating radical, rather than to the participation of the CTC in the propagation step.

Effect of ZnCl2 on the copolymerization of acrylonitrile with N-2-chlorophenylmaleimide

Abstract: The effect of ZnCl2 addition on the reactivity ratios of the system acrylonitirle (AN)-N-2-Chlorophenylmaleimide (2CMI) has been investigated. It has been found that the addition of small amount of ZnCl2 doubles the reactivity of AN while drastically decreasing that of the 2CMI. The viscosity of the copolymers has been measured and was found to decrease with increasing the maleimide and the ZnCl2 concentrations.