Thermoreversible gelation of polyacrylonitrile/dimethylformamide-solution |
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Authors: | J Beckmann D Zenke |
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Institution: | (1) Institute of Polymer Chemistry, Teltow, Germany;(2) Present address: Institut für Organische Chemie, Johannes-Gutenberg-Universität, J. Becher Weg 18-20, Psf. 3980, D-6500 Mainz 1, FRG |
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Abstract: | The thermoreversible gelation of semi-diluted atactic polyacrylnitrile (PAN)/dimethylformamide (DMF)-solutions has been studied. The structural features of PAN/DMF-gels, formed by supercooling have been investigated by DSC-, x-ray- and swelling measurements. A new structural model has been introduced to describe the morphology of the junction zones of PAN/DMF-gels and to also explain the gelation behavior of PAN/DMF-solutions as the structural features of PAN/DMF-gels. The junction zones of a PAN/DMF-gel have been defined as ordered junction zones.A gelation enthalpy of about H=–6 kJ/mol supports the idea that an ordered junction zone is formed by intermolecularly neighboring stereoregular parts of atactic PAN chains due to a nucleation process in the solution. It can be defined as a strongly distributed fringed micelle. |
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Keywords: | Polyacrylnitrile dimethylformamide gelation critical gel concentration junction zones |
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