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Gas permeation resistance of various grades of perfluoroalkoxy–polytetrafluoroethylene copolymers
Author(s) -
Monson L.,
Moon Sung In,
Extrand C. W.
Publication year - 2008
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.28858
Subject(s) - permeation , materials science , comonomer , polymer , crystallinity , solubility , copolymer , polytetrafluoroethylene , polymer chemistry , chemical engineering , composite material , chemistry , membrane , organic chemistry , biochemistry , engineering
The permeation resistance of various grades of perfluoroalkoxy (PFA)/polytetrafluoroethylene (PTFE) copolymers was tested. Specimens were compression molded using two different cooling techniques: a faster one (ice water quench) and a slower one (press cooled). Permeability, diffusion, and solubility coefficients were measured for hydrogen, nitrogen, and oxygen gases. The slow cooled samples always showed much better permeation resistance than those cooled quickly, demonstrating that process can be as important as polymer grade in determining the ultimate permeation resistance of PFA. For a given cooling method, molecular mass (chain length) had no appreciable affect on the permeation resistance. On the other hand, PFA grades with increased comonomer content appeared to have slightly diminished permeation resistance whereas grades with PTFE filler had better permeation resistance. Differences in permeation resistance were attributed to variation in crystallinity arising from differences in molecular architecture and processing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009