Effect of annealing on structure and permeability of poly [(l‐trimethylsilyl)‐l‐propyne]

Abstract

The permeability of annealed poly (l‐(trimethylsilyl)‐l‐propyne) was studied from the viewpoint of structural information obtained from x‐ray diffraction and density. The sample cast from benzene solution had low density (0.82 g/cm³) and high permeability, whereas the annealed sample had a higher density (0.88 g/cm³) and permeability lower by two orders of magnitude. The smaller‐angle x‐ray diffraction peak for each sample, which was likely to reflect the distance between intermolecular chains, increased in intensity and shifted toward higher angle, corresponding to the change of the density with annealing. The logarithmic oxygen permeability was proportional to the density, namely the free volume fraction correlated with the diffusion coefficient and controlled by annealing and swelling by alcohols.