Peculiarities of copolyimide modification by polyvinylpyrrolidone in a viscous state were studied. The differential scanning calometry revealed changes in the morphology and phase transitions of modified copolyamide materials. The increased technological compatibility between the components of copolyamide-polyvinyl pyrrolidone mixture was established. The effect of the modifier on the strength and thermophysical properties of the studied thermoplastic was found. Introduction of polyvinylpyrrolidone contributes to the growth of copolyamide strength under rupture and relative elongation and leads to a certain decrease in Vicat softening point and change of copolyamide technological properties.