Multiwalled carbon nanotube (MWCNT)/epoxy composites are prepared, and the characteristics and morphological properties are studied. Scanning electron microscopy microphotographs show that MWCNTs are dispersed on the nanoscale in the epoxy resin. The glass-transition temperature (T-g) of MWCNT/epoxy composites is dramatically increased with the addition of 0.5 wt % MWCNT. The T-g increases from 167 degrees C for neat epoxy to 189 degrees C for 0.5 wt % CNT/epoxy. The surface resistivity and bulk resistivity are decreased when MWCNT is added to the epoxy resins. The surface resistivity of CNT/epoxy composites decreases from 4.92 x 10(12) Omega for neat epoxy to 3.03 x 10(9) Omega for 1 wt % MWCNT/epoxy. The bulk resistivity decreases from 8.21 x 10(16) Omega cm for neat epoxy to 6.72 X 10(8) Omega cm for 1 wt % MWCNT/epoxy. The dielectric constant increases from 3.5 for neat epoxy to 5.5 for I wt % MWCNT/epoxy. However, the coefficient of thermal expansion is not affected when the MWCNT content is less than 0.5 wt %. (c) 2006 Wiley Periodicals, Inc.