13C NMR studies of thermotropic liquid crystalline poly(γ-alkylaryl L-glutamate)s |
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| Authors: | Ryôta Yamamoto Kazuo Araki Yoshio Imamura Tetsuo Asakura Eisaku Iizuka Shûji Iida |
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| Affiliation: | 1. Department of Chemistry, Faculty of Science, Science University of Tokyo, Kagurazaka, Shinjuku-ku, Tokyo 162, Japan;2. Faculty of Technology, Tokyo University of Agriculture and Technology, Nakamachi 2-Chome, Koganei, Tokyo 184, Japan;3. Institute of High Polymer Research, Faculty of Textile of Science and Technology, Shinshu University, Ueda, Nagano 386, Japan |
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| Abstract: | The molecular motions of three kinds of poly(γ-alkylaryl L -glutamate)s ( 1 – 3 ) having a phenylene or a biphenylylene group and alkyl groups with various length, containing 6 to 22 carbon atoms, were investigated by means of 13C NMR spectroscopy as a function of temperature. The observed range of temperature covers the “crystal-to-liquid-crystal” phase transition temperature, Tm. It was found that these phase transitions are caused by an increase of the motions of aromatic or alkyl groups in the side chain, depending on the samples, and that the motion of main chains of polymers 1 – 3 with α-helical conformation does not occur on the NMR time scale at least up to 160°C. The degree of the mobility of the alkyl chain in the side chain of 1 – 3 depends on their length above Tm. |
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