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The viscoelastic behavior of concentrated polyacrylonitrile/1‐butyl‐3‐methylimidazolium chloride from solution to gel
Author(s) -
Zhu Xinjun,
Saba Hina,
Zhang Yumei,
Wang Huaping
Publication year - 2014
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.23593
Subject(s) - polyacrylonitrile , viscoelasticity , rheology , materials science , polymer , plateau (mathematics) , viscosity , polymer solution , shear rate , polymer chemistry , chloride , thermodynamics , ionic liquid , chemical engineering , shear thinning , shear (geology) , composite material , organic chemistry , chemistry , catalysis , engineering , metallurgy , mathematical analysis , physics , mathematics
The viscoelastic behavior of concentrated polyacrylonitrile (PAN) /1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) solutions at different concentrations and temperatures has been investigated by rheology. For concentrated polymer solutions at low temperature (40°C), the shear viscosity was found to show a raid decrease from the ending of Newtonian plateau. At relatively high shear rate or frequency for the concentrated PAN/[BMIM]Cl solutions, the deviation from the empirical Cox–Merz rule was quite evident, which suggested the formation of heterogeneous structures within these solutions. However, the dependence of G ′ and G ″ on angular frequency presented approximate linearity with similar slope at some temperatures between 100°C and 20°C. All the results lead us to the fact that the gelation has occurred within the concentrated solutions during cooling and the process was found to be thermoreversible. The gelation temperatures of the solutions have exhibited strong concentration dependence. It may be suggested that the microphase separation may be the major reason for the gelation of the concentrated PAN/[BMIM]Cl solutions during cooling process. POLYM. ENG. SCI., 54:598–606, 2014. © 2013 Society of Plastics Engineers