Physical Gels of Syndiotactic Polystyrene With Fragrant Molecules

The morphology of syndiotactic polystyrene (SPS) with several typical fragrant molecules is studied to clarify what solvent conditions can produce SPS gel, which is expected to be a material that can release fragrance for a long period of time. Eight fragrant solvent molecules are employed to dissolve SPS at high temperatures and the morphologies they show after cooling are checked. Their morphologies can be divided into three: a gel with a threedimensional network consisting of a fi brillar structure having the SPS d phase, a paste-like state consisting of a non-lamellar spherulitic structure having the SPS g phase, and a sherbetlike state consisting of a lamellar structure having the SPS b phase. Finally, the necessary conditions of a solvent to be able to form an SPS gel turn out to be its molecular size being less than  160 A 3 and its Fedors’ solubility parameter having a value whose gap from SPS is less than 1.5 (cal/cm 3 ) 1/2 .