Abstract
Syndiotactic polystyrene (sPS) sheets made with three different cooling rates were examined by X-ray diffraction. The mass transport experiments of ethyl acetate were performed from 50℃ to 70℃ in three kinds of sPS samples, as well as gamma-ray irradiated sPS with dosage range from 200 to 1000 kGy. Crystalline sPS can be obtained by furnace and air cooling processes, while amorphous samples by water quenching from the melt. The crystallinity of crystalline sPS were lower after immersing in solvent than before, whereas solvent-induced crystallization occurred in amorphous samples. The transport behavior of ethyl acetate in sPS is an anomalous diffusion and can be divided into two stages. Each stage of sorption curve was fitted with Harmon's model. The activation energies for diffusion (ED) and relaxation processes (EV) were calculated from the Arrhenius plots of D and V. For crystalline sPS, D2 and V2 are larger than D1 and V1, respectively; for amorphous sPS, D2 is also larger than D1, but V2 is smaller than V1. For all kinds of samples, ED in stage 2 is smaller than that in stage 1. For crystalline samples, EV in stage 2 are larger than those in stage 1, but they are almost the same in both stages for amorphous sPS. Comparing crystalline sPS with amorphous sPS, the values of solubility, D and ED are smaller in well-ordered structure than in amorphous structure. The influence of irradiation on sPS is not demonstrative in mass transport experiment.