Study of the Thermal Decomposition Behavior of Poly(vinyl alcohol) with NaHSO4

The thermal decomposition behavior of poly(vinyl alcohol) (PVA) with NaHSO₄ at 280～290°C as well as the optical characteristics and the thermal stability of the resulting thermally decomposed PVA were investigated by means of UV-Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The results suggest that (1) the elimination reactions of side groups in PVA with NaHSO₄ can occur under our conditions resulting in formation of carbon–carbon double and triple bonds; (2) most of the carbon–carbon double bonds were conjugated; (3) the PVA thermally treated with NaHSO₄ could absorb light in the region of 190～600 nm; (4) the thermal stability of the resulting PVA was better than that of PVA without thermal treatment; and (5) compared with the thermal reaction of PVA without NaHSO₄, the addition of NaHSO₄ can promote the thermal elimination of side groups of PVA.