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Investigation into the rheological properties of PES/NMP/nonsolvent membrane‐forming systems
Author(s) -
Li Zhansheng,
Jiang Chengzhang
Publication year - 2001
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.1850
Subject(s) - diethylene glycol , rheology , materials science , rheometer , ethylene glycol , polymer chemistry , membrane , polymer , chemical engineering , viscosity , creep , viscoelasticity , chemistry , composite material , biochemistry , engineering
Abstract From the perspective of a polymer solution, the rheological properties of the popular polyethersulfone (PES)/ N ‐methyl‐2‐pyrrolidone (NMP)/nonsolvent (NS) membrane‐forming system were investigated thoroughly with a controlled stress rheometer (HAAKE RS75, Germany). The scope of the study included measurements of the controlled‐stress flow curve, creep recovery, and dynamic oscillation. H 2 O, 1‐butanol, ethylene glycol, and diethylene glycol were used as NS additives. The effects of the polymer concentration and the quality of the solvent mixture, as characterized by the approaching ratio, on the rheological behavior of the dopes were studied. Up to 38 wt % PES and extremely adjacent to the phase separation (i.e., the approaching ratio of the dope was 0.95), the viscous property dominated all the dopes, which behaved as Newtonian fluids. Moreover, all the membrane‐forming dopes investigated were in the crossover regime in the semidilute region, in which the chains were overlapping but unentangled. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 283–291, 2001