Synthesis of core-shell PFPE@SiO2 nanocapsules and their self-lubrication effect in phenol-formaldehyde resin

To improve the mechanical properties and tribological properties of desirable polymer composites, a novel nanoencapsulated perfluoroyeyeane @ silica (PFPE@SiO2) nanocapsules were used to modify the phenolformaldehyde (PF) resin composites (PFPE@SiO2-PF). These nanocapsules were successfully obtained by interfacial polymerization, exhibited a consistent size ranging from 130 nm to 180 nm, along with a thin shell thickness of 19.4 nm and a high oil -contenting rate of 49.13 wt%. The prepared PFPE@SiO2-PF composites simultaneously demonstrated excellent mechanical properties and tribological performances. Specifically, the compressive strength of the 5 wt%-PF was increased by 33.3% than that of pure PF resin. Moreover, the friction coefficient (COF) of the 25 wt%-PF (50 N) could be reduced by 86.3% (from 0.564 to 0.077) and the wear rate could be reduced by 98.0% (from 69.8 x 10-6 mm3 N-1 m- 1 to 1.4 x 10-6 mm3 N-1 m- 1). The PFPE oil released from the nanocapsules during the friction process produced a transfer film which brought an extremely low COF and wear rate. These results confirmed the excellent self-lubricating property of the PFPE@SiO2-PF composites and presented a potential application in fabricating self-lubricating polymer composites field.