Melt processing of high alcoholysis poly(vinyl alcohol) with different polyol plasticizers

Flexibile high hydrolysis degree poly(vinyl alcohol) (PVA) films with different polyol plasticizers were obtained by melt processing in the presence of water, and the plasticizing effect of polyols was studied. The results showed that with the incorporation of polyols, the torque decreased, suggesting the improved melt flowing ability of PVA. Higher molecular weight polyols with more -OH groups exhibited higher efficiency to improve the melt flowing ability. The incorporation of polyol plasticizers did not change the crystalline structure of PVA but decreased crystalline degrees. The transmittance decreased with the increase in plasticizer content. The flexibility of PVA films was dramatically enhanced after being plasticized with polyols. The polyols with higher molecular weight possessed a higher stablity in PVA films and resulted in less weight loss during the thermal degradation process. It was suggested that a combination of different polyol plasticizers would be a better choice to obtain the PVA films with overall excellent properties.