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Solution behavior of ionomers. III. Sulfo‐EPDM‐modified hydrocarbon solutions
Author(s) -
Lundberg Robert D.
Publication year - 1982
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1982.070271209
Subject(s) - viscosity , solvent , sulfonate , ethylene propylene rubber , polymer , ionomer , xylene , materials science , hydrocarbon , polymer chemistry , copolymer , polar , chemical engineering , thermodynamics , chemistry , organic chemistry , toluene , composite material , sodium , physics , engineering , astronomy
The solution viscosity of polymer thickened hydrocarbons normally decreases markedly as temperature is increased. It has been observed that metal sulfonate ionomers, such as sulfonated ethylene propylene terpolymer, or sulfo‐EPDM, when dissolved in a mixed solvent behave much differently. Specifically, sulfonated ionomers, dissolved in xylene or paraffinic oils with low levels of a polar cosolvent, can provide solutions whose viscosities are either relatively constant or can actually increase with increasing temperature. This isoviscosity effect can be manifested over broad temperature ranges and is mechanistically different from the behavior of conventional polymer solutions. This unusual behavior is explained on the basis of a simple equilibrium involving solvated ion pairs and is shown to be a specific example of a general phenomenon.