Thermodynamic and structural investigations on the different forms of syndiotactic polystyrene intercalates

The occurrence of polymer-solvent intercalates of syndiotactic polystyrene (sPS) in biphenyl, benzophenone, and diphenylmethane has been observed from thermodynamic, structural, and morphological investigations. For each system the temperature-concentration phase diagram has been established by DSC and has allowed one to determine the number of sPS/solvent compounds. Experiments by X-ray diffraction and neutron diffraction bear out the outcomes of T-C phase diagrams of these systems. In addition, these diffraction experiments have shown that the highly solvated form, discovered in sPS/benzene systems [Daniel et al. Polymer 1996, 37, 1273], is more common than expected. We suggest to designate the usual chlathrate form as delta(c)-form while the more solvated form could be named delta(i)-form. Also, another form has been observed in these systems, which possesses a nematic-like order. As this form is also a sPS/solvent compound, we suggest to designate it as delta(N)-form The morphology of each system significantly varies with the solvent.