Construction of micro-thermal conductive network of self-assembled CNTs hybrids with 1D–0D structure

Abstract

In this context, carbon nanotubes (CNTs)/silver nanoparticles hybrids with special 1-dimensional–0-dimensional (1D–0D) structure were successfully fabricated via self-assemble of dopamine followed by reduction reactions of silver cations aiming to synthesize more efficient thermal conductive fillers for the formation of heat flow transfer network in PA6 matrix. FTIR, XRD, TG and TEM revealed the characteristics of functionalized CNTs. Meanwhile, the effect of CNTs hybrids with 1D–0D structure on the construction of heat flow network and thermal conductivity was also investigated. Experimental results showed that thermal conductivity of composites enhanced with increased filler content, the highest thermal conductivity of the PA6/CNTs hybrids composites reached 0.65 W m−1 K−1, which was 2.1 times that of pure PA6 and 32% higher than that of pristine CNTs-filled composites (0.55 W m−1 K−1) with same filler content (10 vol%), and this was ascribed to the better dispersion of fillers and enhanced interfacial interaction between fillers and matrix, as well as the special structure of CNTs hybrids that could abundance the heat transfer path. The crystallinities and dynamic thermal mechanical properties were also analyzed. The enhanced storage modulus (1940 MPa for pure PA6 to 3650 MPa for PA6/CNTs hybrids composites at 5 °C) and higher glass transition temperature along with the change of crystallization behavior of fabricated composites were in accordance with the thermal conductive behavior. The thermal conductive model and its mechanism were then proposed and further confirmed by scanning electron microscopy.