Effect of magnesium chloride hexahydrate on thermal and mechanical properties of starch/PVA films

Starch/poly(vinyl alcohol) (PVA) blend films were prepared from the aqueous solutions containing starch, PVA and magnesium chloride hexahydrate (MgCl2 center dot 6H(2)O). The interaction between MgCl2 center dot 6H(2)O and starch/PVA was studied by Fourier transform infrared spectroscopy. The plasticising effect of MgCl2 center dot 6H(2)O on starch/PVA film was studied by scanning electron microscopy (SEM), X-ray diffraction, thermogravimetric analysis, dynamic mechanical analysis and tensile testing respectively. The water content of starch/PVA films increased with the content of MgCl2 center dot 6H(2)O. The absorbed water can act as the plasticiser for starch/PVA film. The crystals of starch and PVA were destroyed, and the crystallinity of starch/PVA film decreased with the plasticising effect of MgCl2 center dot 6H(2)O and water. SEM micrographs showed that the compatibility between starch and PVA improved with the addition of MgCl2 center dot 6H(2)O. The toughness of starch/PVA film increased with the content of MgCl2 center dot 6H(2)O.