High-precision gravimetric technique for determining the solubility and diffusivity of gases in polymers

✍ Scribed by Betty Wong; Zhiyi Zhang; Y. Paul Handa

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 205 KB
• Volume: 36
• Category: Article
• ISSN: 0887-6266
• DOI: 10.1002/(sici)1099-0488(19980915)36:12<2025::aid-polb2>3.0.co;2-w

✦ Synopsis

An in situ gravimetric technique, employing an electrobalance, is described for determining the solubility and diffusivity of gases in polymers over extended ranges of temperature and pressure. Solubilities of CO 2 in polystyrene at 35ЊC were measured as a test case; the results are in excellent agreement with the literature values determined by the pressure decay method. Solubility and diffusivity results are also reported for PVC-CO 2 at 35ЊC and for PS-1,1,1,2-tetrafluoroethane at 30, 90, and 120ЊC. A comparison with other studies shows the in situ method to be more efficient and precise than the ones based on weighing the gas-saturated polymer under ambient conditions. The kinetics of gas sorption were analyzed in terms of two data reduction techniques to derive diffusion coefficients.