Abstract
This paper investigated the thermal behavior of polyarylsulfone (PSF) films aged by hydrochloric (HCl) and nitric acids (HNO3). The thermal decomposition and glass transition of PSF films were evaluated using thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG curve of untreated PSF film shows a two-stage process, while TG curves of aged films show a three-stage process. The weight loss which was found in the aged films at low temperature region, below 300°C, is considered to be due to the decomposition of PSF with low molecular weight. This suggests that a part of PSF is decomposed by HCl and HNO3. The glass transition temperature (Tg) of PSF decreased as the period of treatment in the acids was increased. However, Tgs of the samples increased when the samples were immersed in 15% HCl, concentrated HCl and 15% HNO3 for more than 120 days. The decrease of Tg showed a good linear relationship with the increase of weight loss near 230°C.
