By means ofin situmelt polycondensation of polyethylenterephathalate accompanied with simultaneous reduction of introduced graphene oxide, the composite of polyethylenterephathalate filled with reduced graphene oxide was prepared. Melting and crystallization of the reduced graphene oxide – polyethyleneterephthalate composite was studied by the differential scanning calorimetry method, and the rheological test was carried out by rotational rheometry and compared to the pristine polyethylenterephathalate. The morphology of the reduced graphene oxide – polyethyleneterephthalate composite was studied using optical microscopy. The reduced graphene oxide was isolated from the reduced graphene oxide – polyethyleneterephthalate composite and characterized by thermogravimetry, X-ray photoelectron spectroscopy and X-Ray diffraction methods. Since a part of polymer could not be removed from reduced graphene oxide particles by trifluoroacetic acid, the hypothesis about probable grafting of polyethyleneterephthalate on reduced graphene oxide sheets was suggested. Rheological behaviour of the reduced graphene oxide – polyethyleneterephthalate composite melt confirms this suggestion. According to the calculations based on thermogravimetry, the reduced graphene oxide, isolated from the reduced graphene oxide – polyethyleneterephthalate composite, consists of about 80% polyethyleneterephthalate.

The work is focused on the study of the influence of the cellulose type and processing parameters on the structure, morphology, and permeability of cellulose films. The free volume of the cellulose films was evaluated by the sorption of n-decane, which is a non-solvent for cellulose. The structural features of the membranes and their morphology were studied using X-ray diffraction, IR spectroscopy, SEM, and AFM methods. The characteristic features of the porous structure and properties of cellulose films regenerated from cellulose solutions in the N-methylmorpholine-N-oxide (NMMO) and cellophane films were compared. Generally, cellulose films obtained from solutions in NMMO have a higher permeability and a lower rejection (as measured using Orange II dye) as compared to cellophane films. It was also found that the cellulose films have a higher ultimate strength and modulus, whereas the cellophane films are characterized by higher elongation at break.

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 ¹H 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.