Molecular weight and concentration effects on gel/sol transitions in a segmented rigid-rod polyimide solution

Sung Koo Lee, Stephen Z D Cheng, Zongquan Wu, Chul Joo Lee, Frank W. Harris, Thein Kyu, Jen Chang Yang

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Abstract

Gel/sol and order/disorder transitions can be observed in a segmented rigid-rod polyimide solution at different concentrations and molecular weights. This polyimide was synthesized from 3.3',4,4'-biphenyltetracarboxylic dianhydride and 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl in refluxing 3-cresol in a one-step process. Above about 140°C, the polymers are completely soluble in 3-cresol in a concentration range up to 12(w/w)%. During cooling, the hot solutions undergo a mechanical sol/gel transition to form thermally reversible gels. In the gel state, an ordered structure develops. Both the gel/sol and order/disorder transitions are dependent upon concentration, temperature, and molecular weight, but the two transitions exhibit different kinetics. Possible mechanisms of these transitions are discussed.

Original languageEnglish
Pages (from-to)115-122
Number of pages8
JournalPolymer International
Volume30
Issue number1
Publication statusPublished - 1993
Externally publishedYes

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ASJC Scopus subject areas

  • Polymers and Plastics

Cite this

Lee, S. K., Cheng, S. Z. D., Wu, Z., Lee, C. J., Harris, F. W., Kyu, T., & Yang, J. C. (1993). Molecular weight and concentration effects on gel/sol transitions in a segmented rigid-rod polyimide solution. Polymer International, 30(1), 115-122.