Structural Phase Transitions of Syndiotactic Polystyrene upon the Guest Extraction Process

摘要

In this work, the effects of initial morphology/crystalline form and the guest molecules used for the preparation of syndiotactic polystyrene (sPS) co- crystals, on the structural phase transitions of sPS upon the guest extraction process were systematically investigated. For that purpose, samples having two different initial morphologies such as amorphous and γ form were used as the starting materials and guests such as chloroform and toluene were used for the preparation of sPS co-crystals. Selective extraction of guest molecules resulted in complex phase transitions in the host structure. In the case of toluene-treated amorphous samples, the structure transformed into the δ (δ_e) form. On the other hand, the chloroform- treated amorphous samples transformed into the mixture of nanoporous δ (δ_e) and ε (ε_e) forms. When chloroform-treated g form samples were used for the guest extraction, the ε (ε_e) form with channel-shaped cavities was obtained. In contrast, when toluene-treated γ form samples were for used guest extraction, the co-crystal structure transformed to its initial crystalline form, i.e., γ form, instead of forming nanoporous structure.