Home – Home – Jornals – Chemistry for Sustainable Development 2020 number 3

Rubber-like elastic cryogels were formed from a two-component solution of polyvinyl alcohol in water after a freezing-thawing cycle, and their rheological properties are investigated. The interest in such environmentally friendly polymer cryostructures having viscoelastic properties is due to the fact that they are currently in high demand in the northern regions of the country. Cryogels are promising structural materials used for the development of new arctic technologies for oilfield engineering and for strengthening seasonally thawing soil in the permafrost zone, as well as for the construction and arrangement of hydraulic structures. As a result of the studies of the properties of cryostructuring agents, it was revealed that due to the mechanical action of external loads, elastic moduli of deformed cryogel samples decrease monotonously with time. Elastic moduli are traditionally used to quantitatively characterise the physical and mechanical properties of Hookean materials. The results of comparative experiments conducted by different researchers using the same cryogel samples are interpreted ambiguously due to the inconstancy of the elastic moduli of viscoelastic systems. In this work, the possibility and necessity to use cryogel relaxation time values as a quantitative criterion for describing the rheological properties of polyvinyl alcohol cryogels are experimentally substantiated. The values of the relaxation time of cryogels are proposed to be used instead of cryogel elasticity moduli to evaluate the viscoelastic properties of polymer systems in future design calculations.