Miscibility of PVC/PEO blends by viscosimetric, microscopic and thermal analyses

The miscibility of PVC with PEO, PVC/PEO blends, was investigated by viscosimetric, microscopic and thermal analyses. Three samples of PVC with different molecular weights were used. The presence of attractive forces among the polymers was evaluated according to the Sun theory by determination of the α parameter from the viscosimetric data. Thermal analyses were based on the depression of the melting temperature. Viscosimetric and thermal results showed that the PVC/PEO blends are miscible. However, the existence of PVC rich domains, smaller than 0.1 μm in blends of PVC/PEO, was observed by microscopic analysis. Polymer–polymer interaction parameters, determined by depression of the melting temperature are negative and showed to be dependent on the molecular weight of PVC. The miscibility of the PVC/PEO blend was explained as a result of donor–acceptor interactions between chlorine atoms of PVC, as a weak acceptor species, and oxygen atoms of the PEO, as a donor species.