Novel nanocomposites PCNs and f-PCNs were prepared by the mixture of PC/PMMA/PS and MWCNTs and functionalized MWCNTs by HNO3 and H2SO4 (f-MWCNTs). The new prepared nanocomposites, pure polymer and polymer blend (PC/PMMA/PS) were characterized by FTIR, mechanical and electrical properties. No observable change occurred in FTIR of PC/PMMA/PS in comparison with PCNs and f-PCNs due to the addition of very minute amount of MWCNTs and f-MWCNTs i.e., 0.1 wt.% and 0.3 wt.%, respectively. The modulus of PC/PMMA/PS blend decreased where the modulus was high with 0.1 wt.% using 10 min cycle time at 270 oC for PCNs and with 5 min cycle time for f-PCNs