The effect of graphene oxide cross-linking and ionization on the crystallization behavior, and the electrical and thermal conductivity of a nylon-66 nanocomposite

Abstract

Recently, nylon-66 materials have begun to be researched due to their excellent properties. However, their low thermal and electrical conductivities may limit their application. In this study, we report the fabrication of an electrically and thermally conductive composite (GO–PPD/NAAK/PA-66) made with nylon-66 (PA-66) and large-scale graphene oxide loaded with potassium naphthalene acetate (GO–PPD/NAAK) for the first time (GO: graphene oxide; PPD: p-phenylenediamine; NAAK: potassium naphthalene acetate). PPD could overlap the GO sheets and expand the interlayer spacing to form thermally and electrically conductive networks in the PA-66 matrix. Simultaneously, NAAK allows the modified GO to disperse in the PA-66 matrix more uniformly via reducing the crystallinity of PA-66. It was observed that the addition of PPD and NAAK reduced the crystallinity of PA-66, leading to extensive thermally and electrically conductive networks in the PA-66 matrix, as verified using DSC and SEM measurements. Good interfacial compatibility between PA-66 and modified GO could be induced via the formation of hydrogen bonds between them. Conductivity data indicated that, in comparison to neat PA-66, the electrical conductivity of GO–PPD/NAAK/PA-66 increased from 1.41 × 10⁻¹⁴ S cm⁻¹ to 2.52 × 10⁻⁴ S cm⁻¹ with 10.0 wt% GO–PPD/NAAK. More importantly, the thermal conductivity increased by about 119% with 10.0 wt% GO–PPD/NAAK.