Degradation and its temperature dependence of poly(methyl methacrylate)(PMMA) in the blend film of PMMA/SAN were investigated via in-situ X-ray photoelectron spectroscopy(XPS). The results show that thermal degradation of PMMA takes place at 185, 130, 80 ℃ and even room temperature due to the existence of monochromatic X-ray. Furthermore, the degradation rate depends crucially on the experiment temperature.
