Nanoparticles of 12-(2-aminoethyl)amino]propyl-heptaisobutyl-polysilsesquioxane were added (0.5 and 1% by mass) to modify mech. and thermal properties as well as morphology of polyamide 6 and polyoxymethylene nanocomposites. The addn. resulted in an improvement of melt flow index, tensile strength, elongation at break, Young modulus (tension) hardness and impact-tensile strength. A small increase in melting and crystn. temps. and in crystallinity degree as well as a decrease in melting and crystn. enthalpies were also obsd.