Gas transport parameters, density and free volume of nanocrystalline poly-2,6-dimethylphenylene oxide

• Published in: Polymer (Guilford) 2021-06, Vol.226, p.123804, Article 123804
• Main Authors: Alentiev, A.Yu, Levin, I.S., Buzin, M.I., Belov, N.A., Nikiforov, R.Yu, Chirkov, S.V., Blagodatskikh, I.V., Kechekyan, A.S., Kechekyan, P.A., Bekeshev, V.G., Ryzhikh, V.E., Yampolskii, Yu.P.
• Format: Article
• Language: English
• Subjects: Amorphous materials; Carbon dioxide; Crystal structure; Crystallinity; Density; Diffusion; Gas transport; Low temperature; Molecular weight; Molecular weight distribution; Parameters; Permeability; poly(phenylene oxide); Polymer blends; Polymers; Semi-crystalline polymers; X-ray diffraction
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2021.123804

Poly(2,6-dimethylphenylene oxide-1,4) (PPO) belongs to a fairly investigated group of polymers that, nevertheless, provokes permanent research interest. The current study is focused on a combination of various physicochemical methods of polymer testing (DSC; molecular weight distribution; surface area by low-temperature adsorption isotherms of nitrogen and carbon dioxide; X-Ray diffraction analysis; hydrostatic measurement of density; gas permeability and diffusion measurement) with variation of molecular weight and different states of polymer samples (amorphous, semi-crystalline, biaxial-oriented). The alteration of the density, gas permeability and diffusion parameters is evaluated through modeling of PPO as a polymer-polymer blend material with amorphous, nano-sized crystalline (≤7 nm), and so-called rigid amorphous fraction (RAF) phases. The estimation of the phase properties of PPO samples allows to conclude that the permeability and diffusion characteristics decline in a row crystalline > amorphous > RAF. [Display omitted] •PPO with a crystallinity of ≥60% shows high gas permeability (P(O2) ~ 40–60 Barrers).•The density of the PPO crystalline phase is less than that of the amorphous phase.•PPO can be considered a three phase system with rigid amorphous fraction (RAF).•The permeability and diffusion decline in a row crystalline > amorphous > RAF.•Estimates of the density and gas transport parameters of PPO phases are obtained.