LAUSR

A blend of crystallizing polyimide and newly synthesized partially crystalline multiblock (segmented) copoly(urethane—imide), consisting of 75 wt % copoly(urethane—imide) and 25 wt % polyimide, was prepared and studied by thermal gravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, and melt rheology. Blend samples were prepared by mixing copoly(urethane—imide) and polyimide prepolymers in an N -methyl-2-pyrrolidone solution, in which the subsequent thermal or chemical imidization of the system components was performed. The properties of the initial polyimide, copoly(urethane—imide), and the blend were compared. The results of studies by differential scanning calorimetry and dynamic mechanical analysis demonstrate the presence of a crystalline soft polyester phase in the copoly(urethane—imide) structure and of the crystalline hard imide phase in the blend structure, which suggests the crystallization suppression in samples of the blend. The dynamic viscosity of the melt of chemically imidized copoly(urethane—imide) and blend samples is lower than that of their thermally imidized analogs. Dynamic mechanical analysis shows that the initial copoly(urethane—imide) behaves as a thermoelastoplastic. The blends consisting of copoly(urethane—imide) and thermoplastic polyimide are similar in properties to polyimide thermoplastics for structural purposes.