Abstract
Acetone transport in polycarbonate without and with irradiation of 254 nm wavelength UV exposure have been investigated. The experimental mass transport with various doses are fitted with Harmon’s model. These data can be curve fitted well by the model proposed by Harmon et al. The characteristic parameters of diffusion coefficient (D) and velocity (v) satisfied the Arrhenius equation for all irradiation doses. In the figure of log (D) versus 1/T, the slope changes appreciably at the transition point (about -2℃). At the temperature range below the transition temperature, the slopes are almost the same before and after the exposures. But at the temperature range above the transition temperature, the data of four doses are overlapped. It is indicated that the structure of irradiated polycarbonate for acetone transport are similar in this ranges. These phenomena were attributed to the solvent-induced crystallization in polycarbonate. Furthermore, the molecular weight and glass transition temperature of polycarbonate decreased with increasing the ultraviolet dose. This result of experiment confirms that polycarbonate occurred photo-Fries rearrangement during ultraviolet exposure with wavelength of 254 nm irradiation.