Simultaneously enhanced mechanical properties and thermal properties of ultrahigh‐molecular‐weight polyethylene with polydopamine‐coated α‐alumina platelets

Abstract Polydopamine (PDA) was employed to modify micrometric Al2O3 platelets to improve the interfacial compatibility between α‐Al2O3 powder and ultrahigh‐molecular‐weight polyethylene (UHMWPE). The structure of PDA‐coated Al2O3 and UHMWPE composites was investigated via Fourier transform infrared spectroscopy, scanning electron microscopy and X‐ray photoelectron spectroscopy. The thermal stability and mechanical performance of the samples were also evaluated. It is clear that UHMWPE/PDA‐Al2O3 composites exhibit better mechanical properties, higher thermal stability and higher thermal conductivity than UHMWPE/Al2O3 composites, owing to the good dispersion of Al2O3 powder in the UHMWPE matrix and the strong interfacial force between the macromolecules and the inorganic filler caused by the presence of PDA. The tensile strength and the tensile elongation at break of UHMWPE/PDA‐Al2O3 composite with 1 wt% PDA‐Al2O3 are 62.508 MPa and 462%, which are 1.96 and 1.98 times higher than those of pure UHMWPE, respectively. The thermal conductivity of UHMWPE/PDA‐Al2O3 composite increases from 0.38 to 0.52 W m−1 K−1 with an increase in the dosage of PDA‐Al2O3 to 20 wt%. The results show that the prepared PDA‐coated Al2O3 powder can simultaneously enhance the mechanical properties and thermal conductivity of UHMWPE. © 2018 Society of Chemical Industry