The design and development of self-lubricating materials
can reduce
friction and wear in industrial activities to satisfy higher demands
for environmental sustainability. Silica nanoparticles, as a representative
of inorganic nanomaterials, have the advantages of low thermal expansion
coefficient, large specific surface area and pore volume, adjustable
particle size, and easy functionalization. When used to modify single-component
polymer materials, silica materials can effectively improve the wear
resistance performance of polymer substrates by enhancing their mechanical
properties. However, the enhancement of self-lubricating properties
of polymers by silica materials is less effective than that achieved
by liquid lubricants. In this paper, liquid lubricants such as dimethyl
silicone oil (DSO) and perfluoropolyether lubricating oil (PFPE) were
loaded using mesoporous silica nanoparticles (MSNs), and the oil content
was about 24 and 48 wt %, respectively. The oil-loaded MSNs (MSNs-DSO
or MSNs-PFPE) were filled into a polyoxymethylene (POM) matrix, and
a POM-based composite with self-lubricating properties was prepared
by a hot pressing process. The materials were tested and analyzed
by a thermogravimetric analyzer, a Fourier infrared analyzer, a scanning
electron microscope, a three-dimensional profile analyzer, a multifunctional
friction and wear tester, a universal material testing machine, and
an X-ray photoelectron spectroscopy analyzer. Compared to pure POM,
the coefficient of friction and wear rate of POM-based composites
containing 5 wt % MSNs-DSO were reduced by 75.3% and 69.2%, respectively.
During the friction process, the lubricant components in the composite
are released from the POM matrix under load and friction heat to migrate
toward the friction interface, forming a corresponding transfer tribofilm
that avoids direct contact between the POM matrix and the friction
counterpart so that the material has excellent self-lubricating properties.