Polymer−Solvent Interactions in Crystalline δ Form of Syndiotactic Polystyrene Viewed from the Solvent-Exchange Process in the δ Form and the Solvent Evaporation Phenomenon in the Thermally Induced δ−γ Phase Transition

Abstract

The δ form, one of various crystalline forms of syndiotactic polystyrene (sPS), is a complex between sPS and solvent molecules. This crystalline form shows a solvent exchange between the originally absorbed solvent B and the newly supplied solvent A when the δ form sample was exposed to the solvent A atmosphere. We have carried out the time-resolved infrared spectral measurement during this solvent-exchange process and found that the solvent-exchange rate was almost common to any pair of solvents where the solvents A and B were toluene, chloroform, or benzene. On the other hand, when the δ form sample was heated above 150 °C, it transferred to the γ form having no solvent molecules in the crystal lattice. The temperature, where most of solvent molecules were evaporated from the sample, was almost common to any kind of solvent originally absorbed in the δ form, as already pointed out by Gowd et al. [Macromolecules 2002, 35, 8509]. All these phenomena, i.e., the solvent-exchange phenomenon and the solvent e...