Effect of Introduction of Phenolic Antioxidants on the Thermo-Oxidative Stability and Gas Permeability of Poly(4-methyl-2-pentyne)

The thermo-oxidative stability and gas transport properties of poly(4-methyl-2-pentyne) (PMP) samples of the mixed configurational composition (50% cis-units) in the presence of phenolic antioxidants Irganox 1076, Irganox 1010, Vulkanox BHT, and Rianox 1520 differing in the nature and structure of substituents on the benzene ring is studied. The annealing of PMP films at 140°С demonstrates that the films with the added Irganox 1076 and Irganox 1010 maintain the strength and stability of gas transport properties for at least 150 h of total heating after moderate decrease in permeability (∼30%) for the first 48 h of heating. PMP films with Vulkanox BHT and Rianox 1520 upon 48 h of heating at 140°С show an increase in gas permeability coefficients, indicating the onset of polymer degradation, and after 100 h of heating they are destroyed. The wide-angle X-ray diffraction of the films with the most effective stabilizers Irganox 1076 and Irganox 1010 reveals a decrease in interchain distances upon annealing which provides evidence for an increase in the packing density of macromolecules as a result of thermally activated relaxation.