Nanoparticles (NP) filled permanently antistatic poly(vinyl chloride) (PVC) composites, constituted of dibutyl phthalate (DBP) and antistatic plasticizer (AP) which included bis[2-(2-methoxyethoxy)ethyl]phthalate doped with sodium perchlorate (NaClO4), were prepared in a Haaka torque rheometer. Surface resistivity measurement, mechanical test, scanning electron microscopy (SEM) investigation, and thermal gravimetric analysis (TGA)-differential scanning calorimetry (DSC) analysis were used to investigate the comprehensive properties of PVC/AP/NP (100/40/x) (A40/NP) and PVC/AP/DBP/NP (100/40/40/x) (A80/NP) composites. The results demonstrated that the surface resistivity of A40/NP composites was lower than that of pure A40 composites at a humidity of 60% and 0.1% as the nano SiO2 or TiO2 content is 2 phr, respectively. Moreover, the surface resistivity of A40 composites was decreased by about half an order of magnitude even at the humidity of 0.1% when 2 phr of NP was added. The surface resistivity of A80/NP composites achieved the optimum value as the SiO2 and TiO2 content were 1 phr and 2 phr, respectively. Because the DBP functioned as small molecule plasticizer which endowed PVC composites with comparatively large free volume, the surface resistivity of A80/NP composites is much lower than that of A40/NP composites. The tensile strength and elongation at break of A40/NP (100/2) and A80/NP (100/2) were increased to some extent with respect to pure PVC/AP composites. DSC-TGA analysis and rheological properties demonstrated that NP filled PVC composites processed good thermostability and thermoprocessability. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 3221-3227, 2013