Effect of tacticity on permeation properties of poly(methyl methacrylate)

Abstract

Abstract The effect of stereoregularity on gas permeation properties of poly(methyl methacrylate) (PMMA) was investigated. The gas permeability coefficients for He, H 2 , O 2 , N 2 , Ar, CH 4 , and CO 2 at 35°C near atmospheric pressure have been measured for three different PMMAs. Apparent diffusion and solubility coefficients were obtained from time lag data, and these were compared with data for a commercial PMMA previously reported. The permeability, solubility, and diffusion coefficients increase as the content of syndiotactic sequences increases. These observations are consistent with more dense packing of the isotactic form in the glassy state that stems in part from its lower glass transition temperature. The transport behavior for a 50:50 isotactic/syndiotactic blend was also studied. These so‐called stereocomplexes exhibit permeation behavior comparable to other weakly interacting miscible blend systems.