Enhancing carbon nanotubes dispersion in thermoplastics for the development of multifunctional composites

The excellent electrical, mechanical and thermal properties along with the high specific surface area of carbon nanotubes make them a strong candidate as functional fillers for polymer matrices in view of developing a multifunctional light-weight composite. However, the significant challenge in achieving a good dispersion of these nanotubes in the host polymer due to their inert chemical surface and tendency to exist as agglomerates inhibits their theoretical potential. Thermoplastic polymers, specifically olefins present a complex scenario for achieving good carbon nanotube dispersion owing to their high melt viscosity and incompatible surface energies with carbon nanotubes. Process parameter optimization and the usage of an economical reactive processing additive lead to an extremely good carbon nanotube dispersion in polypropylene, and consequently result in excellent electrical and thermal properties of the composite at very low filler loadings. Incorporation of glass fibers as secondary fillers lead to a substantial improvement in the mechanical properties of the bi-filler composite whilst preserving the enhancements in electrical and thermal properties caused by carbon nanotube addition. This led to a multifunctional composite with excellent electrical, structural and thermal properties with significant potential for light-weight product development.