Temperature dependence of the conformation of isotactic polystyrene in toluene

✍ Scribed by Helms, J. B. ;Challa, G.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1972
• Tongue: English
• Weight: 478 KB
• Volume: 10
• Category: Article
• ISSN: 0449-2978
• DOI: 10.1002/pol.1972.160100803

✦ Synopsis

Abstract

In order to obtain information about a possible helix–coil transition of isotactic polystyrene (i‐PS) at 80°C in toluene, as has been reported in other solvents, solution properties were examined at temperatures between 10 and 110°C. Use was made of viscometry, high‐resolution nuclear magnetic resonance, infrared spectroscopy, calorimetry, and light scattering. No distinct transition was found at 80°C but rather a second‐order transition between 62 and 65°C. A similar transition occurred in toluene solutions of atactic polystyrene. The transition may be attributed to a sudden change in the mobility of the phenyl side‐group of the polymer. From this study it is concluded that i‐PS has a helical conformation in toluene, the mean helix length decreasing smoothly with increasing temperature.