Features of the Gas-Permeable Crystalline Phase of Poly-2,6-dimethylphenylene Oxide

• Published in: Polymers Vol. 14; no. 1; p. 120
• Main Authors: Alentiev, Alexander Yu, Levin, Ivan S, Belov, Nikolay A, Nikiforov, Roman Yu, Chirkov, Sergey V, Bezgin, Denis A, Ryzhikh, Victoria E, Kostina, Julia V, Shantarovich, Victor P, Grunin, Leonid Yu
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 29.12.2021; MDPI
• Subjects: Activation energy; Crystal structure; Crystallinity; Fourier transforms; free volume; gas permeability; gas sorption; Gas transport; Gases; Infrared spectroscopy; Lifetime; Magnetic induction; Molecular sieves; NMR; Nuclear magnetic resonance; Organic chemistry; organic molecular sieves; Permeability; poly-2,6-dimethylphenylene oxide; Polymer films; Polymers; Positron annihilation; semi-crystalline polymers; Spectrum analysis; Thermodynamic properties; Russia; poly-2,6-dimethylphenylene oxide; free volume; gas permeability; organic molecular sieves; semi-crystalline polymers; gas sorption
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym14010120

Poly-2,6-dimethylphenylene oxide (PPO) film samples with varying degrees of crystallinity (from 0 to 69%) were obtained by means of different techniques. The films were studied by various physicochemical methods (Fourier-transform infrared spectroscopy, positron annihilation lifetime spectroscopy, X-ray diffraction, and H nuclear magnetic resonance relaxation). Solubility coefficients of gases in the PPO samples were measured via sorption isotherms of gases by volumetric technique with chromatographic detection. The apparent activation energy of permeation and the activation energy of diffusion of all gases were estimated based on temperature dependences of gas permeability and diffusivity for amorphous and semi-crystalline PPO in the range of 20-50 °C. The peculiarities of free volume, density, and thermal properties of gas transport confirm the nanoporosity of the gas-permeable crystalline phase of PPO. So, the PPO can be included in the group of organic molecular sieves.