Study on miscibility of poly(vinyl chloride) and polyepichlorohydrin by viscometric and thermal analysis

Viscometric analysis was carried out to study the miscibility of poly(vinyl chloride) (PVC) and polyepichlorohydrin (PECH) in various solvents, tetrahydrofuran (THF), methyl ethyl ketone (MEK) and dimethylformamide (DMF). The Krigbaum–Wall criterion is used here to evaluate the miscibility of the two components, and Δb is introduced which can be calculated from the viscosity curves. The results show that their attractive forces are predominant when dissolved in THF, while in MEK and DMF repulsive forces play a leading role. This is attributed to different solubilities of the two polymers in the three solvents and to different influences of the solvents on the conformation of the polymers. Thermal measurement was performed by differential scanning calorimetry to investigate the glass transition temperature (Tg) of the blends prepared from the three solvents. Phase separation is observed for the samples made from MEK and DMF, while for THF the sample exhibits a single phase.

We have investigated the miscibility between poly(vinyl chloride) and polyepichlorohydrin in various solvents by viscometric and thermal analysis. Same results have been obtained that different solvents influence the miscibility of polymers to a large extent. Therefore, the effect of solvents could not be ignored.Figure optionsDownload as PowerPoint slideHighlights
► We used reduced viscosity to evaluate miscibility of PVC/PECH blend in three solvents.
► We employed the Krigbaum–Wall theory to examine its miscibility in these solvents.
► The two methods gave the same result of miscibility sequence in the three solvents.
► Solubility parameter plays an important role in miscibility in various solvents.
► DSC was used to characterize Tg to examine miscibility in another way.