Studies on the preparation of hydrolyzed starch-g-PAN (HSPAN)/PVA blend films––Effect of the reaction with epichlorohydrin

Absorbent hydrolyzed starch-g-PAN (HSPAN)/polyvinylalcohol (PVA) blend films crosslinked with epichlorohydrin (ECH) were prepared to overcome the phase separation and improve the mechanical properties of blend films. The absorbency of HSPAN/PVA blend films decreased with PVA contents due to the reduction of HSPAN contents which is known to play a major role in absorbing ability of the film. And also the absorbency decreased with the ECH contents due to the crosslinking reaction. As far as the solubility is concerned, it increased with PVA contents which is water soluble. But because of the crosslinking reaction between HSPAN and PVA by ECH, the solubility decreased with ECH contents. In the mechanical properties, the strength as well as the strain at break of the HSPAN/PVA blend films were improved very much if compared with HSPAN film, and those mechanical properties were improved even more by the reaction with ECH. The DSC thermograms of HSPAN films showed two major endothermic peaks at 32 and 128 °C, while those of PVA film showed two major endothermic peaks at 49 and 190 °C. In the non-crosslinked blend films, each four endothermic peak was apparent. But as the ECH content increased, both peaks at 128 and 190 °C disappeared and a new peak appeared at the intermediate temperature. In other words, the compatibility of blend films was increased by the reaction with ECH. Also, from the results of TGA, it was confirmed that the thermal degradation of blend films was decelerated by the crosslinking reaction.