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Toluene vapour sorption behaviours in syndiotactic polystyrene (SPS) film were measured at 25°C by the quartz crystal microbalance method. The sorption isotherm of this system was concave toward the pressure axis below the activity of toluene vapour (p/p0 ˆ 0.3), indicating a strong interaction between toluene vapour and sorption sites in the mesophase consisting of TTGG conformation. On the other hand, the sorption isotherm of toluene vapour in atactic polystyrene film showed a normal good solvent type and could be described by Flory–Huggins thermodynamics. In addition, the structural changes in SPS film by toluene vapour sorption were characterized by Infrared spectroscopy. The absorbance at 933 cm ⫺1, which is assigned to TTGG conformation, was found to be constant below p/p0 ˆ 0.3; however, it increased above p/p0 ˆ 0.3 and was saturated above p/p0 ˆ 0.6. These results showed that toluene vapours penetrated into the pre-existing sorption sites composed of TTGG conformation to form the clathrate structure (d form) below p/p0 ˆ 0.3. Furthermore, in the range of p/p0 ˆ 0.3–0.6, the sorption of toluene vapour could induce a large increase in the ordered structure (d form), i.e., TTGG confirmation. The changes in the non-clathrate structure with toluene (a form) composed of TT conformation, could be characterized by the absorbance at 1222 cm ⫺1. It was confirmed that the a form could be also increased by toluene vapour sorption above p/p0 ˆ 0.4. The sorption enthalpy of toluene vapour (DHs), estimated from sorption isotherms showed a negative value below p/p0 ˆ 0.6, but showed a positive value above p/p0 ˆ 0.6, even though the polymer–good solvent pair. This result also supports the structural organization in SPS film by toluene vapour sorption.

Посилання на статтю:

The structural organization in syndiotactic polystyrene film induced by toluene vapour sorption / Kimiaki Tsutsui, Toshiyuki Katsumata, Yusuke Yamamoto, Hiroki Fukatsu, Hiroaki Yoshimizu, Takatoshi Kinoshita, Yoshiharu Tsujita // Polymer. – 1999. – N 40. – P. 3815–3819.

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