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

Polydopamine (PDA) was employed to modify micrometric Al 2 O 3 platelets to improve the interfacial compatibility between α -Al 2 O 3 powder and ultrahigh-molecular-weight polyethylene (UHMWPE). The structure of PDA-coated Al 2 O 3 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-Al 2 O 3 composites exhibit better mechanical properties, higher thermal stability and higher thermal conductivity than UHMWPE/Al 2 O 3 composites, owing to the good dispersion of Al 2 O 3 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-Al 2 O 3 composite with 1 wt% PDA-Al 2 O 3 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-Al 2 O 3 composite increases from 0.38 to 0.52 W m −1 K −1 with an increase in the dosage of PDA-Al 2 O 3 to 20 wt%. The results show that the prepared PDA-coated Al 2 O 3 powder can simultaneously enhance the mechanical properties and thermal conductivity of UHMWPE. © 2018 Society of Chemical Industry