The kinetics of homogeneous hydrolysis of polyacrylonitrile in an aqueous solution of sodium car bonate and the chemical structure of the resulting copolymer are studied by FTIR spectroscopy, 13 C NMR analysis, and titration methods. It is found that hydrolysis in the presence of sodium carbonate does not include the stage of amidine formation and does not result in the complete exhaustion of nitrile groups in a polymer. The designed partial hydrolysis method permits the use of polyacrylonitrile for the synthesis of the copolymer with a predominant unit alternation; this copolymer is identical in terms of chemical structure to the Rohacell copolymer obtained through block copolymerization of acrylonitrile and methacrylic acid.

On the basis of potentiometric investigations of the kinetics, a new mechanism of aniline polymerisation is proposed, including the formation of a charge-transfer complex with the participation of the monomer; also, a kinetic model is constructed and some of its parameters are evaluated.

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Standard methods were used to investigate the physicomechanical characteristics of the main parts of endotracheal tubes produced by six leading world manufacturers. It was shown that the articles have statistically significant, substantial differences in the physicomechanical properties of their main working units: the main tube and the sleeve. The sleeve is the least strong part on which the functionality of the entire article depends. The best strength characteristics are possessed by the Curity sleeve, but at the same time the Curity main tube possesses practically no thermal plasticity. The Rush main tube possesses high thermal plasticity but has the least strong sleeve. Most balanced from the viewpoint of physicomechanical characteristics is the Portex tube. Having sufficient tube elasticity and strength, among the investigated tubes it has the highest thermal plasticity with minimum hardness at body temperature and a sleeve of high strength.