The Effect of Thermal Annealing on the Structure and Gas Transport Properties of Poly(1-Trimethylsilyl-1-Propyne) Films with the Addition of Phenolic Antioxidants.

The thermally activated relaxation of poly(1-trimethylsilyl-1-propyne) (PTMSP) samples of various -/-compositions (50-80% units of -configuration) in the presence of phenolic antioxidants of various structures was investigated. It was pointed out that polymers with a high content of -units exhibited greater thermal-oxidative stability due to the greater flexibility of the -enriched macrochains. The use of hindered phenols as antioxidants made it possible to prevent the process of thermally initiated oxidative degradation. At the same time, the most effective stabilizing agents were antioxidants with larger molecules such as Vulkanox BKF, Irganox 1010, and Irganox 1076. It was shown that the permeability coefficients of stabilized PTMSP during thermal treatment initially slightly decreased (by 20-30%), which, according to the X-ray diffraction data, was associated with an increase in the density of the macrochain packing, and during further heating remained practically unchanged. Note that for the -enriched samples, no signs of oxidation or decrease in the transport characteristics were observed during polymer heating for 240 h at 140 °C.