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Viscoelastic properties of polyacrylonitrile gels: dependence of sol‐gel transition on concentration and aging time
Author(s) -
Tanaka Yutaka
Publication year - 2003
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200351028
Subject(s) - polyacrylonitrile , viscoelasticity , gel point , materials science , dimethylacetamide , transition point , polymer chemistry , glass transition , constant (computer programming) , chemical engineering , composite material , thermodynamics , chemistry , rheology , polymer , solvent , organic chemistry , physics , engineering , computer science , programming language
Dynamic viscoelasticity was observed for polyacrylonitrile solution in dimethylacetamide in the process of sol‐gel transition. The gel was prepared by the freezing and thawing method, i.e., the solution was frozen at −50°C and then kept at 25°C so as to undergo gelation. The longer the freezing time, the shorter was the gelation time. Also the higher the concentration, the shorter the gelation time. The strength of the network, S and critical exponent n at the transition point were evaluated. The S value increased with increasing concentration and was constant in value in spite of the variation of freezing time when the concentration of the solution was constant.