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Preparation of vinyl amine‐ co ‐vinyl alcohol/polysulfone composite membranes and their carbon dioxide facilitated transport properties
Author(s) -
Salih Alsamani A. M.,
Yi Chunhai,
Hu Jiayang,
Yin Lijuan,
Yang Bolun
Publication year - 2014
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.40043
Subject(s) - permeance , vinyl alcohol , polysulfone , crystallinity , copolymer , membrane , polymer chemistry , materials science , facilitated diffusion , selectivity , vinyl acetate , chemistry , chemical engineering , nuclear chemistry , polymer , organic chemistry , catalysis , composite material , biochemistry , engineering
A vinyl amine–vinyl alcohol copolymer (VAm–VOH) was synthesized through free‐radical polymerization, basic hydrolysis in methanol, acidic hydrolysis in water, and an anion‐exchange process. In the copolymer, the primary amino groups on the VAm segment acted as the carrier for CO 2 ‐facilitated transport, and the vinyl alcohol segment was used to reduce the crystallinity and increase the gas permeance. VAm–VOH/polysulfone (PS) composite membranes for CO 2 separation were prepared with the VAm–VOH copolymer as a selective layer and PS ultrafiltration membrane as a support. The membrane gas permselectivity was investigated with CO 2 , N 2 , and CH 4 pure gases and their binary mixtures. The results show that the CO 2 transport obeyed the facilitated transport mechanism, whereas N 2 and CH 4 followed the solution–diffusion mechanism. The increase in the VAm fraction in the copolymer resulted in a carrier content increase, a crystallinity increase, and intermolecular hydrogen‐bond formation. Because of these factors, the CO 2 permeance and CO 2 /N 2 selectivity had maxima with the VAm fraction. At an optimum applied pressure of 0.14 MPa and at an optimum VAm fraction of 54.8%, the highest CO 2 permeance of 189.4 GPU [1 GPU = 1 × 10 −6 cm 3 (STP) cm −2 s −1 cmHg −1 ] and a CO 2 /N 2 selectivity of 58.9 were obtained for the CO 2 /N 2 mixture. The heat treatment was used to improve the CO 2 /N 2 selectivity. At an applied pressure of 0.8–0.92 MPa, the membrane heat‐treated under 100°C possessed a CO 2 permeance of 82 GPU and a CO 2 /N 2 selectivity of 60.4, whereas the non‐heat‐treated membrane exhibited a CO 2 permeance of 111 GPU and a CO 2 /N 2 selectivity of 45. After heat treatment, the CO 2 /N 2 selectivity increased obviously, whereas the CO 2 permeance decreased. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131 , 40043.