Samples of poly[1–(trimethylsilyl)–1–propyne] were kept for about 4 years in ambient conditions. The permeability and diffusion coefficients were examined and found to be decreased by 1–2 orders of magnitude. To ascertain the nature of the changes underwent during long‐term storage of this polymer, several physicochemical methods were applied: positron annihilation, wide‐angle X‐ray diffraction, spin probe, and density evaluation. These studies indicated that a decrease of free volume and more close chain packing took place during the aging process. IR spectroscopy and 13C‐NMR showed that oxygen‐containing products appeared in the polymer after long‐term storage. This should result in a certain decrease in the rigidity of the backbone chains and more intensive interchain in‐teractions, and, hence, in a decrease in the free volume of the aged polymer. © 1993 John Wiley & Sons, Inc.

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We have used 1 H and 13 C NMR spectroscopy to study the composition of pine resin balsams from Scotch pines grown in different regions of the Republic of Belarus. We have established that their chemical composition does not depend very much on the region where they are grown or the level of contamination of the forests by radioactive and industrial emissions. Prolonged storage of the balsams leads to a substantial change in their compositions, due to isomerization of the resin acids.

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