Fabrication of Bifunctional UHMWPE Composites With Self‐Lubricating and Self‐Repairing Capabilities via Core‐Shell MSNs ‐ PFPE @ PEW Particles

In mechanical systems, the energy dissipation and wear caused by friction usually lead to the failure of materials during their service life, thereby driving the demand for polymer composite materials with both tribological properties and self‐repairing capabilities. Studying polymer composites with self‐lubrication and self‐repairing functions is an effective approach. Perfluoropolyether (PFPE) was infused into the micropores of mesoporous silica nanoparticles (MSNs) and polyethylene wax (PEW) was used to encapsulate the oil‐carrying particles to prepare MSNs‐PFPE@PEW with a core‐shell structure, which was combined with ultra‐high molecular weight polyethylene (UHMWPE) as a filler to prepare UHMWPE/MSNs‐PFPE@PEW composites. The material possesses both self‐lubricating and self‐repairing properties. Compared with pure UHMWPE, the friction coefficient and wear rate of the composite material supplemented with 10% MSNs‐PFPE@PEW can be reduced by 72.22% and 60.47%, respectively, and 59.74% of the wear damage and 60.47% of the scratch damage can be repaired. PFPE migrates to the friction interface under the action of load and friction heat during the friction process to form a friction transfer film, which plays a lubricating role. PEW undergoes a phase change upon heating treatment, which is able to fill in the damage on the surface of the composite material, and play a role in repairing it. This study provides a new idea for the development of self‐lubricating and self‐repairing bifunctional composites.