In this work, we studied the temperature dependence of the intrinsic viscosity, the Huggins constant, which characterizes the resistance of macromolecular coils to the penetration of solvent molecules and the second virial coefficient (A2) into them. As is known, the Huggins constant K҆ is another constant that, along with the intrinsic viscosity [h], characterizes the rheological properties of a diluted solution, and is determined by the size, shape and properties of segments of polymer molecules and solvent molecules. Ultimately, K҆ determines (characterizes) the tendency of the solvent into the coil, or the resistance of the polymer when the solvent penetrates into the coil. For highly dilute solutions, long elastic micromolecules curl up into a ball and an increase in viscosity caused by the disgust of a separate macromolecule by the action of a pair arising from friction with a solvent due to the difference in the flow rate in different parts of the solution is expressed by the viscosity characteristic [h]. Indeed, the change in intrinsic viscosity with temperature is directly related to the dependence of the thermodynamic quality of the solvent. If the quality of the solvent improves with increasing temperature (A2 increases), the coil swells more, the resistance to flow increases, [𝜂] increases. And if the quality of the solvent deteriorates with increasing temperature (A2 decreases), the interaction of the segments of the macromolecule with each other prevails over the interaction of water molecules with the segments, then the penetration of water into the coil worsens (Huggins constant increases), the coil shrinks, [𝜂] decreases.