Solvent effects on microwave dielectric relaxation in poly(ethylene glycols)

✍ Scribed by Sengwa, R. J.

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 207 KB
• Volume: 45
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199801)45:1<43::aid-pi902>3.0.co;2-1

✦ Synopsis

This paper reports the results of a systematic study of microwave dielectric relaxation times of poly(ethylene glycols), average molecular weight 200È9000, in dilute solutions of benzene at 9É83 GHz. These results are compared with the values of relaxation times obtained earlier in carbon tetrachloride solutions. This shows that the average relaxation times and the relaxation time q 0 corresponding to segmental reorientation are inÑuenced by the solvent q 1 environment. The variation in chain Ñexibility in these polymers with the increase in degree of polymerization and formation of intra-and inter-molecular hydrogen bonding in benzene and carbon tetrachloride solutions is discussed with the help of relaxation data. The relaxation time corresponding to group q 2 rotations has been determined. It is found that the value is independent of q 2 solvent environment and degree of polymerization, and may be attributed to the rotation of chain wOH end-groups around the CwO bonds in dynamic equilibrium, with the formation of a Ðve-membered ring due to intra-molecular hydrogen bonding at the end of the chain.

1998 SCI. ( . Int. 45 43È46 (1998)

Polym