Studies on the Effect of Glass Transition on the Crystalline Transition in Syndiotactic Polystyrene – Solvent Complexes

Summary: Amorphous syndiotactic polystyrene (sPS) was crystallized at room temperature in Norbornadiene (bicyclo[2,2,1]‐hepta‐2,5‐diene), Mesitylene (1,3,5‐ Trimethylbenzene), 3‐Carene (3,7,7‐trimethyl bicyclo[4,1,0]hept‐3‐ene) and DMN (1,4‐Dimethylnaphthalene) to form the sPS‐solvent complex ( δ form) with respective solvent molecules. In situ HTFTIR studies showed that the δ form to γ form transformation temperature occurs well below the glass transition temperature of sPS, which is depressed due to the presence of solvent in the amorphous phase; higher the solvent content in the complex, lower the transition temperature. Glass transition temperatures determined by Modulated differential scanning calorimetry (MDSC) coincide with the transition temperatures, indicating that the δ form transforms into γ form at the glass transition temperature for these complexes. Such a behavior is very different from the behaviour of the sPS‐ solvent complexes formed by dichloromethane, chloroform, toluene, o ‐dichlorobenzene, decalin (cis‐trans) etc. and for these complexes the transition occur well above the T g. 1