Abstract:

The conductive composites based on polypropylene （PP）， polycaprolactone （PCL）， graphite and carbon nanotubes （CNTs） were prepared by melt blending， and their microstructure， melting flow rate， mechanical properties， electrical conductivity， electro-thermal performance， and thermal stability were characterized. The results indicated that the fracture strength of PP increased by 4.375 MPa with the addition of PCL. However， its mechanical properties decreased by 73.5 % when graphite and CNTs were further added. The incorporation of graphite and CNTs effectively reduced the resistivity of PP， leading to a transition from insulator to semiconductor with a resistivity of 7.83 × 10⁶ Ω·m. According to the thermogravimetry analysis， the introduction of PCL significantly improved the thermal stability of PP， resulting in an increase in initial decomposition temperature from 368.88 °C to 398.95 °C. Its initial decomposition temperature further increased to 408.78 °C with the addition of graphite and CNTs.

Key words: polypropylene, composite material, carbon nanotube, electric heating material