Interface-engineered functionalized graphene oxide reinforced polyamide 6 composites with enhanced mechanical and thermal properties

The advancement of the automotive and mechanical industries has placed higher demands on the thermal conductivity of polyamide 6 (PA6). However, the weak interfacial bonding between graphene oxide (GO) and the PA6 matrix aggravates phonon scattering, which in turn increases interfacial thermal resistance and limits the improvement of composite thermal conductivity. To address this issue, hexamethylene diisocyanate (HDI) was employed as an interfacial modifier, and GO-HDI/PA6 composites featuring strong covalent bonding at the nanofiller/matrix interface were fabricated via anionic ring-opening polymerization. As a result, incorporating a low content of GO-HDI could significantly enhance both the thermal conductivity and tensile strength of the composites. At 2 wt% GO-HDI, the thermal conductivity of the PA6 composite increased to 0.821 W/m·K, representing a 258.5 % improvement compared to neat PA6. Moreover, with only 0.2 wt% GO-HDI, the tensile strength of the composite improved by 27.9 %, reaching 50.9 MPa. The outstanding thermal conductivity and mechanical performance were attributed to the uniform dispersion of the nanofillers and their strong interfacial bonding with the matrix, which were further verified by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses. This composite holds significant application potential in various fields that demand stringent thermal management and structural performance requirements.