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Effect of the casting solvent on the free‐volume characteristics and gas permeability of poly[1‐(trimethylsilyl)‐1‐propyne] membranes
Author(s) -
Bi Jing Jing,
Wang C. L.,
Kobayashi Y.,
Ogasawara K.,
Yamasaki A.
Publication year - 2002
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.11433
Subject(s) - cyclohexane , propyne , membrane , tetrahydrofuran , polymer chemistry , solvent , toluene , materials science , trimethylsilyl , chemistry , chemical engineering , organic chemistry , biochemistry , engineering
The effect of the casting solvent on the structure of poly[1‐(trimethylsilyl)‐1‐propyne] (PTMSP) membranes was investigated experimentally. The PTMSP membranes were cast from solutions of cyclohexane, toluene, and tetrahydrofuran; the membranes were characterized by the positron annihilation lifetime spectroscopy (PALS) technique and by gas‐permeation measurements of O 2 , N 2 , and CO 2 . The decay curves from the positron annihilation lifetime spectroscopy gave the best fit when two long‐life components (τ 3 and τ 4 , τ 3 < τ 4 ) were employed. This suggests that two types of free volume existed in the PTMSP membranes. The size and number density of τ 4 , which was characteristic for PTMSP, decreased in the following order of the casting solvents: cyclohexane > toluene > tetrahydrofuran. The order was consistent with the order of gas permeability. A good correlation was observed between the permeability and the structural parameter that denoted the free‐volume size and the number density of τ 4 . © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 497–501, 2003