TY - JOUR
T1 - Molecular weight and concentration effects on gel/sol transitions in a segmented rigid-rod polyimide solution
AU - Lee, Sung Koo
AU - Cheng, Stephen Z D
AU - Wu, Zongquan
AU - Lee, Chul Joo
AU - Harris, Frank W.
AU - Kyu, Thein
AU - Yang, Jen Chang
PY - 1993
Y1 - 1993
N2 - 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.
AB - 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.
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M3 - Article
AN - SCOPUS:0027384876
SN - 0959-8103
VL - 30
SP - 115
EP - 122
JO - Polymer International
JF - Polymer International
IS - 1
ER -