Abstract: Crude CNTs were first treated with an acid solution and then subjected to air oxidation, particles of metal catalyst and amorphous carbons on the surface were effectively removed and the CNTs were purified. The purified CNTs were used in EP/CNTs thermal conductive composites. The thermal conductivity, impact strength, flexural strength of EP/CNTs composites were investigated. When the content of purified CNTs was 1.5 wt %, the impact strength, flexural strength, and thermal conductivity were 24.95 kJ/m2, 127.2 MPa, and 1.237 W/（m·℃）, respectively.

Key words: epoxy resin, carbon nanotubes, non-destructive purification, thermal conductivity