Subnanometer hole properties of CO2-exposed polysulfone studied by positron annihilation lifetime spectroscopy |
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| Authors: | J-P Yuan H Cao E W Hellmuth Y C Jean |
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| Institution: | Department of Chemistry, University of Missouri–Kansas City, Kansas City, Missouri 64110 |
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| Abstract: | Positron annihilation lifetime (PAL) spectroscopy has been employed to study subnanometer hole properties in polysulfone (PSF). In this study, hole properties of size, fraction, and distribution of PSF exposed to CO2 are reported. In the PSF/CO2 system, the hole size and fraction significantly increase and the free-volume distribution broadens as a function of CO2 pressure in the range of 0–1000 psi. Hysteresis in hole properties is observed during CO2 sorption/desorption cycle. The high sensitivity of PAL results due to CO2 exposure in PSF is explained in terms of the microstructural changes in the polymer matrix, i.e., filling penetrant and plasticization, gas hydrostatic pressure effect, and creation of free volumes and holes. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 3049–3056, 1998 |
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| Keywords: | positron annihilation free volume polysulfone CO2 gas exposure |
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