TRANSPORT-PROPERTIES OF MESOMORPHIC SYNDIOTACTIC POLYSTYRENE

Amorphous syndiotactic polystyrene (sPS) films were annealed at 110 de grees and 115 degrees C for 24 h. The annealing at the higher temperat ure produced the mesomorphic form of sPS, characterized by conformatio nal order, as shown both by the presence of the zigzag band in the inf rared spectrum and by the presence of characteristic peaks in the x-ra y diffractogram. The crystalline form was riot formed at the investiga ted temperatures. Differential scanning calorimetry of the mesomorphic sample shows that the transformation of the mesophase into the crysta lline phase occurs during the heating run. The transport properties of dichloromethane show that the mesophase is impermeable to the vapors at low activity and becomes permeable at higher activities. At low act ivity it is therefore possilble to derive the fraction of impermeable phase, which corresponds to the fraction of mesophase. This fraction w as about 50%.