ENHANCEMENT OF MECHANICAL AND ELECTRICAL PROPERTIES OF EPOXY-BASED COMPOSITES FILLED WITH INTACT OR OXIDIZED CARBON NANOTUBES

摘要

Electrically conductive polymers are widely required in various industrial fields. The paper presents the influence of oxidized and surfactant-stabilized multiwalled carbon nanotubes (MWCNTs) of content (0.005–10 wt.%) on the mechanical and electrical characteristics of epoxy-based composites. Stronger mechanical properties of thermoset composites have been revealed with introduction of oxidized MWCNTs rather than of initial ones. Impact strength and breaking stress at bending of epoxy composites filled with 0.005% ordinary or oxidized MWCNTs were increased by 40% and 60%, respectively. Surfactant stabilization of MWCNTs by means of adding 0.01–0.001 wt.% of isopropoxytristearoxytitanate (TTS) leads to an increase in the nanotubes resistance to oxidation. The electrical conductivity of final composites was measured after they were filled with 0.1 to 10 wt.% MWCNTs, and various mechanisms of conductivity depending on the filler content were proposed. Tenfold enhancement of electrical conductivity (from 10 ~( –12 ) up to 10 ~( –2 ) S/cm) has been revealed for composites filled with 10 wt.% of MWCNTs, meanwhile the use of oxidized nanotubes in all experiments gave a stronger effect.