Permeability of poly(4-methylpentene-1) with different degrees of isotacticity

Permeability coefficients, X-ray diffractograms, and lifetime positron annihilation spectra were measured for poly(4-methylpentene-1) samples with a content of isotactic fraction in the 58-98% range. It was shown that the variation of the degree of isotacticity of polymers does not change the permeability coefficients for different gases. No changes were observed in the degree of crystallinity, in the features of X-ray diffractograms, or in the parameters of lifetime spectra; these results indicate that the free volume of poly(4-methylpentene-1) is not sensitive to its stereoregularity