Molecular motion of syndiotactic poly(α-methylstyrene) in solution studied by carbon-13 n.m.r. relaxation measurements |
| |
Authors: | Yoshio Inoue Yoshihiro Kawamura Tetsuo Konno |
| |
Affiliation: | Department of Polymer Chemistry, Tokyo Institute of Technology, O-okayama, Meguroku, Tokyo 152, Japan |
| |
Abstract: | The carbon-13 n.m.r. spin-lattice relaxation times, nuclear Overhauser enhancement factor (NOE), and line widths have been measured for a syndiotactic poly(α-methylstyrene) in solutions in toluene-d8 and o-dichlorobenzene-d4 as a function of temperature from 40° to 163δC. The single correlation time model of relaxation is inadequate to explain the data of spin-lattice relaxation time and NOE. But, within experimental error, these relaxation data in two solvents over a full temperature range can be interpreted in terms of either the Cole-Cole or the log-χ2 distributions of correlation times, or a conformational jump model proposed by Monnerie et al. The internal rotation of the methyl group is relatively rapid, while that of the phenyl ring is slow and practically overshadowed by the backbone segmental reorientation over the temperature range examined. The solvent dependence of relaxation data was discussed. |
| |
Keywords: | Poly(α-methylstyrene) spin-lattice relaxation time nuclear Overhauser effect molecular motion nuclear magnetic resonance polymer conformation |
本文献已被 ScienceDirect 等数据库收录! |
|