Some Properties of Polymethylmethacrylate-Polyisobutylene Rubber Blends

798-801Polymethylmethacrylate (PMMA) was solution blended with medium and low molecular weight polyisobutylene rubber samples (PIBm and PIBl) in toluene. The compatibility of the blends was assessed from density and viscometric methods at 2 per cent total solid content of solution. The experiment al densities were observed to be lower than the theoretical values assuming additivity of volumes of the polymers and the solvent for both PIB samples. The plots of relative viscosities against composition were found to be non-linear. The experimental values for reduced viscosities were found to be lower than calculated values using Krigbaum-Wall equation for all blend solutions. A visual study of the blend films showed marked phase separation and impaired clarity. The tensile mechanical test on the blend films showed a higher yield stress and a larger area under the stress-strain curve compared to the pure PMMA, suggesting that blending with the PIB rubber toughened PMMA. The density and viscometric methods have again been proved to be an easy and reliable method for assessing polymer-polymer compatibility