Morphological, dynamic mechanical, rheological and impact strength properties of the PP/PVB blends: the effect of waste PVB as a toughener

Abstract

In this study, compatibilized PP/PVB blends were prepared and their morphological, dynamic mechanical, rheological and Izod impact strength properties were investigated. Thermal and crystallization behavior of the blends were also studied. SEM micrographs showed a reduction in the particle size and size distribution of the PVB domains by adding PP-g-MA up to a certain content, beyond which the particle diameter increased. This is ascribed to saturation of the interface with compatibilizer and micelle formation in the matrix. Furthermore, the migration of some fraction of plasticizer from the PVB phase into the PP matrix was revealed by dynamic mechanical analysis (DMA). Differential scanning calorimetry (DSC) analysis indicated the immiscibility of the blend components and also the role of the PVB particles as nucleating agents for crystallization of the PP. Based on the rheological properties, the role of the compatibilizer in improving compatibility and homogeneity was more pronounced for the blends containing 15 wt% PVB. This is originated from the plasticizer effect on the interactions between the compatibilizer and the blend components. Finally, Izod impact test results showed that the PP/PVB blends had a higher impact strength compared to the pure PP. This implies the fact that waste PVB film could act as an elastomer and improve the impact resistance of brittle polymers. The results of the present work showed that waste PVB could be used in a new application instead of disposal or incineration, which is important from economical and environmental points of view.