Gas sorption and transport in semicrystalline poly(4-methyl-1-pentene)

Abstract The solubility of CO 2 and CH 4 plus permeability coefficients for these and other gases were measured for a series of poly(4-methyl-1-pentene) polymers with crystallinity levels ranging from 20% to 75%. The crystallinity was varied through thermal treatment and by addition of a comonomer that permitted thermally-induced crosslinking. An extrapolation, assuming a two-phase model, of the sorption results to 100% crystallinity indicates a finite solubility for CO 2 and CH 4 in the crystal (about 25–30% of the solubility for the amorphous phase). Regression analysis of the permeation data using a two-phase transport model indicated that diffusion occurs at finite rates in the crystal. This is contrary to the usual situation for polymers like polyethylene but is consistent with the unusual fact that the density of the poly(4-methyl-1-pentene) crystal is slightly less than that of the amorphous phase. The diffusion rate in the crystal appears to become nil as the dimensions of the gas molecules exceed the estimated gap sizes between chains in the crystal.

[1]  A. Michaels,et al.  Diffusion of Gases in Polyethylene Terephthalate , 1963 .

[2]  Douglas M. Ruthven,et al.  Diffusion of CO2 in 4A and 5A zeolite crystals , 1980 .

[3]  J. Lai,et al.  Preparation of vinylpyridine irradiation-grafted poly(4-methyl-pentene-1) membrane for oxygen enrichment , 1986 .

[4]  V. Vardanian,et al.  Effect of radiation on the crystallinity of low-density polyethylene , 1987 .

[5]  J. Schultz,et al.  Polymer materials science , 1974 .

[6]  V. T. Stannett.  SPE International Award Address–1978 Barrier properties and migration problems of plastics , 1978 .

[7]  H. L. Fein,et al.  Gas Transport in Thermally Conditioned Linear Polyethylene , 1964 .

[8]  V. Boekelheide.  [2n]Cyclophanes: paracyclophane to superphane , 1980 .

[9]  W. Higuchi,et al.  Theoretical analysis of diffusional movement through heterogeneous barriers , 1960 .

[10]  J. Boon,et al.  Structural studies of crystalline poly(p‐phenylene oxides) II. Poly(2.6‐diphenyl p‐phenylene oxides) , 1970 .

[11]  P. Zoller.  The specific volume of poly(4‐methylpentene‐1) as a function of temperature (30°–320°C) and pressure (0–2000 kg/cm2) , 1977 .

[12]  W. Higuchi.  A New Relationship for the Dielectric Properties of Two Phase Mixtures , 1958 .

[13]  H. Yasuda,et al.  Isobaric measurement of gas permeability of polymers , 1970 .

[14]  W. Vieth,et al.  Transport properties and their correlation with the morphology of thermally conditioned polypropylene , 1969 .

[15]  Douglas M. Ruthven,et al.  Principles of Adsorption and Adsorption Processes , 1984 .

[16]  P. Doty,et al.  Temperature Dependence of Water Vapor Permeability , 1946 .

[17]  R. Porter,et al.  Characterization of uniaxially drawn poly(4-methyl-pentene-1) , 1987 .