Filling-level effect on the physical properties of MgBr2- and MgCl2-filled poly(vinyl acetate) films

摘要

The structural properties of poly(vinyl acetate) (PVAc) films filled with different levels of MgBr2 or MgCl2 were investigated. Differential scanning calorimetry revealed that, at certain filling levels of MgBr2 or MgCl2, two new transitions appeared. The first one was due to the alpha relaxation (T-alpha) associated with a crystalline region, and the second was due to the melting temperature (T-m). This implies that a crystalline phase was formed in the polymeric matrix. Changes occurring in T-alpha, T-m, and the melting peak area as a function of the filling level were examined. The X-ray diffraction (XRD) pattern revealed that the pure PVAc film was amorphous. However, the addition of MgBr2 or MgCl2 led to the formation of a crystalline phase in the polymeric matrix that depended on the filling level. XRD also demonstrated that the structural changes depended not only on the metal ions but also on the halide ions. Scanning electron microscopy images for the studied samples were examined. (C) 2002 Wiley Periodicals, Inc. [References: 22]