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Starch/poly(vinyl alcohol) (PVA) blend films were prepared from the aqueous solutions containing starch, PVA and magnesium chloride hexahydrate (MgCl2.6H2O). The interaction between MgCl2.6H2O and starch/PVA was studied by Fourier transform infrared spectroscopy. The plasticising effect of MgCl2.6H2O 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 MgCl2.6H2O. 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 MgCl2.6H2O and water. SEM micrographs showed that the compatibility between starch and PVA improved with the addition of MgCl2.6H2O. The toughness of starch/PVA film increased with the content of MgCl2.6H2O.

The effects of ultraviolet absorbers (UVAs) on the UV-irradiation behaviours of rigid PVC were studied through Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. In addition, the absorption behaviours of these UVAs in non-polar and polar solvents were characterised and the solution photolysis experiments of these UVAs in ethanol were investigated in the absence and presence of a free radical initiator during the UV irradiation. The results showed that the protection efficiency to photo-degradation of PVC was in the following order:2,4,6-tri(2-hydroxy-4-butoxylphenyl)-1,3,5-triazine (U3) > 2-(2H-benzotriazol-2-yl)-6dodecyl-4-methyl phenol (U2) > 2-hydroxy-4-n-octoxy-benzophenone (U1). This protection efficiency was related to the chemical structures of the UVAs, especially the intermolecular hydrogen bond (IMHB). In a polar solution, such as dimethyl sulfoxide, the absorption corresponding to the IMHB of U3 was intact, while that of U1 disappeared. The free radical initiator weakened the intensity of the absorption, accelerating the destruction of the IMHB.