Premium
Dynamic deposition of polyacids on porous membrane supports
Author(s) -
Ozari Y.,
Tanny G.,
JagurGrodzinski J.
Publication year - 1977
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.1977.070210221
Subject(s) - polyelectrolyte , acrylic acid , copolymer , membrane , cellulose acetate , polymer chemistry , chemical engineering , materials science , sorption , cellulose , cellulose triacetate , chemistry , organic chemistry , polymer , composite material , adsorption , biochemistry , engineering
Abstract Poly(acrylic acids), poly(styrenesulfonic acid), and their block and random copolymers were tested for their ability to form dynamic membranes on partially cured asymmetric cellulose acetate. Chemically modified porous polypropylene (Celgard) was also used as a support for poly(acrylic acid). Salt rejections, water fluxes, and streaming potentials of membranes were tested under hyperfiltration conditions. Sorption of the polyelectrolytes by the cellulose acetate supports was studied using spectrophotometric, 22 Na tracer, and electron microscopy techniques. The dynamic membrane formation was noted only for poly(acrylic acid) and for its 1:4:1 block copolymer with poly(styrenesulfonic acid). The uneffectiveness of other polyelectrolytes was discussed in terms of a negative zeta potential of cellulose acetate. The increase in salt rejection ( R ) due to the polyelectrolyte is strongly dependent on the initial R i of the support. Sharp maxima in the Δ R ‐versus‐ R i curves have been noted for R i in the range of 40–55%. The most significant improvement in the hyperfiltration characteristics of cellulose acetate was attained with the 1:4:1 block copolymer. Flux of 17 gfd at 350 psi and R = 93% was obtained in short‐term tests for a 0.1 N feed solution. Long‐term tests did not reveal any flux or salt rejection decline for membranes in which poly(acrylic acid) was complexed with phosphoramidic groups grafted onto Celgard.