STABILIZATION OF POLYVINYL CHLORIDE/POLYSTYRENE BLENDS WITH A MODIFIED MONTMORILLONITE

Abstract

The demixing resistance of the heterogeneous polyvinyl chloride (PVC)/polystyrene (PS) system was analyzed in the presence of a modified commercial clay (Cloisite 10A, C10A). The blends were prepared using tetrahydrofuran (THF) as solvent. The C10A organoclay was concentrated in the PVC-rich phase, despite the structural similarity between the organic modifiers of the clay and the PS. Localization of the clay had a significant effect on the stability of the blends. Unlike when the clay was located in the dispersed phase rich in PVC, the presence of the organoclay in the PVC as a continuous phase, prevented spontaneous demixing, reduced the size of dispersed PS domains and promoted interfacial adhesion. The increase in basal spacing observed in the diffractograms is consistent with the intercalation of polymer chains between the clay layers. The micrographs obtained by TEM revealed the coexistence of exfoliated, intercalated and tactoid structures.