ISOTACTIC POLYSTYRENE CIS-DECALINE MIXTURES - PHASE-DIAGRAM AND MOLECULAR-STRUCTURES

Organized structures grown from iPS/cis-decalin solutions (ranging from 5% to 50% w/w) have been studied by several techniques. From DSC experiments the thermal behavior has been investigated as a function of the annealing temperature. The temperature-concentration phase diagram has been established. From neutron diffraction experiments the short range molecular order has been determined. We show that between the gel state formed at high undercooling and the crystalline state obtained at low undercooling there exist two intermediate phases: the s-phase, already described by Klein et al., and the p-phase. Except for the crystalline state all the other phases contain intercalated solvent molecules. The gel state displays nematic-like order, whereas the s-phase is reminiscent of smectic arrangements. The p-phase is less solvated and can be described as a peritectic system. Preliminary neutron scattering experiments show that chain-folding reappears in the s-phase, whereas it was shown to be absent in the gel phase.