TRANSPORT CHARACTERISTICS AND OTHER PHYSICOCHEMICAL PROPERTIES OF AGED POLY (1-(TRIMETHYLSILYL)-1-PROPYNE)

Samples of poly[1-(trimethylsilyl)-1-propyne] were kept for about 4 ye ars in ambient conditions. The permeability and diffusion coefficients were examined and found to be decreased by 1-2 orders of magnitude. T o ascertain the nature of the changes underwent during long-term stora ge of this polymer, several physicochemical methods were applied: posi tron annihilation, wide-angle X-ray diffraction, spin probe, and densi ty evaluation. These studies indicated that a decrease of free volume and more close chain packing took place during the aging process. IR s pectroscopy and C-13-NMR showed that oxygen-containing products appear ed in the polymer after long-term storage. This should result in a cer tain decrease in the rigidity of the backbone chains and more intensiv e interchain interactions, and, hence, in a decrease in the free volum e of the aged polymer.