**5. Conclusion**

In this chapter, we compared the properties of composite materials based on nanostructured silicon carbide and carbon nanotubes with modified and unmodified surfaces obtained on three types of polyimide matrices (matrix No. 1 based on pyromellitic dianhydride and 4,4′-oxydianiline; matrix No. 2 based on 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride and p-phenylenediamine; and matrix No. 3 based on pyromellitic dianhydride and 4-[4-(4-aminophenoxy) phenoxy] phenylamine).

The influence of different amounts of nanostructured silicon carbide and carbon nanotubes on the viscosity of the intermediate precursor (polyamide acid solution), as well as the thermal stability and mechanical properties of final composites based on the polyimide binder, was obtained and tested on three types of polyimide matrices.

It was found that for composites based on nanostructured silicon carbide and carbon nanotubes, the optimal content of inorganic filler is the interval for silicon carbide from 0.05 to 0.1 wt.%, for single-walled carbon nanotubes from 0.1 to 0.75 wt.%.

It was found that the effect of inorganic fillers on the properties obtained by thermal imidization in a high-temperature solvent of powders of composite materials depends to a large extent on the chemical nature of the polyimide matrix. The influence of the inorganic filler on the properties of the film composite material obtained by the stepwise high-temperature imidization in a vacuum medium is the same and practically independent of the structure of the matrix.
