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O 2 and N 2 gas permselectivity of alternating copoly(vinylidene cyanide–vinyl acetate)
Author(s) -
Hachisuka Hisao,
Kito Hitoshi,
Tsujita Yoshiharu,
Takizawa Akira,
Kinoshita Takatoshi
Publication year - 1988
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.1988.070350518
Subject(s) - sorption , membrane , nitrogen , permeation , vinyl acetate , annealing (glass) , cyanide , polymer chemistry , oxygen , materials science , langmuir , adsorption , chemistry , nuclear chemistry , inorganic chemistry , polymer , organic chemistry , copolymer , composite material , biochemistry
The sorption and permeation of oxygen and nitrogen in and through alternating copoly(vinylidene cyanide–vinyl acetate) [copoly(VDCN–VAc)] ( T g = 176°C) membranes annealed for different periods just below T g , 160°C, were investigated over the pressure range from 100 to 1000 cmHg. The dual‐mode sorption and mobility models were used to analyze the results. A sub‐ T g annealing of copoly(VDCN–VAc) caused a slight decrease in the amount of sorption in the membranes. This decrease in the amount of oxygen and nitrogen sorption can be attributed to a decrease in the Langmuir sorption capacity term, C ′ H , with increasing sub‐ T g annealing period. The densification of copoly(VDCN–VAc) membranes caused simultaneously by the annealing remarkably reduced diffusion coefficients for both gases. The reduction in diffusion coefficients of Langmuir mode, D H , for both gases was found to be larger than that of Henry's law mode, D D . Furthermore, permselectivity of oxygen to nitrogen, the ratio of permeability coefficient of oxygen to nitrogen ( P O 2 / P N 2 ), reached to 11.8 for the copoly(VDCN–VAc) annealed for 30 h. Evidently the reduction of D H and D D for nitrogen with increasing annealing period was much larger than that for oxygen.