KINETICS FEATURES OF STRUCTURE FORMATION IN A THERMOTROPIC POLYMER SYSTEM

In the present work the rheological properties of 3% solution of methylcellulose (MC-2000S), a polymer with lower critical dissolution temperature, used as a base component of thermotropic compositions developed by the Laboratory of Petroleum Colloidal Chemistry IPC SB, used for enhanced oil recovery, were investigated. Measurements were performed on a Haake Viscotester iQ rheometer equipped with a measuring system of CC25 coaxial cylinders during heating and cooling of the sample at different rates of temperature change in rotational and oscillation modes. Temperature control was carried out by a Peltier element built into the rheometer. In the rotational mode, the dependences of viscosity on shear rate, viscosity dependences on temperature at a constant value of shear rate were recorded, and in the oscillation mode, the dependences of the elastic modulus component on temperature at a given value of strain (0.01) and frequency (1 Hz) were recorded. It is shown that on viscosity-temperature dependences after reaching the maximum corresponding to structurization there is a sharp decline associated with mechanical destruction of the sample, and the elastic modulus after reaching the maximum reaches a plateau - the forming structure is preserved. It was found that the dependences of viscosity and elastic modulus on temperature, recorded during heating and cooling of the sample at a fixed rate, differ significantly - hysteresis of rheological properties is observed. The hysteresis picture for the viscosity-temperature dependences obtained in the rotational mode changes significantly when the heating/cooling rate is changed, while no such dependence is observed for the curves obtained in the oscillatory mode at a given strain. For citation: Kozhevnikov I.S., Bogoslovskii А.V. Kinetics features of structure formation in a thermotropic polymer system. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 8. P. 26-31. DOI: 10.6060/ivkkt.20256808.9t.