Superior tough, highly wear durable and self-lubricating epoxy composite co-enhanced by soft and hard nanomaterials

Despite many efforts are being undertaken to design high tribo-performance epoxy nanocomposite, it still remains a great challenge to comprehensively address the interface issue and poor mechanical strengths for real engineering requirements. This work reports a facile yet efficient strategy (synergism of soft and hard materials) to coordinate the interface-property relationship. Herein, we composited graphene with molybdenum disulfide to fabricate rGO-MoS₂ interlayered nanostructure as hard solid lubricant, as the hyperbranched polysiloxane with unique flexible Si[sbnd]O[sbnd]C backbone was synthesized via facile polymerization as soft component within epoxy network. These two nanomaterials can be well used to construct EP composite for easy processing, and their merits regarding lubricity and toughening are well exerted, especially the interface could be improved without surface treatment. The optimized material with superior impact strength (23.5 ∼ 37.4 kJ·m⁻²), low friction coefficient (0.42 ∼ 0.16) and volume wear rate (70.6 % reduction) was obtained with respect to previous counterparts. Interestingly, TEM of ultra-thin resin slice found that hyperbranched polysiloxane could affect the distribution and nanostructured interface of graphene/MoS₂, encouraging a facile and low-cost approach towards surface engineering of high-performance polymer composite. Besides, the tribo-mechanism and nano-reinforced mechanism were investigated and discussed in detail. In light of the compelling effects, this work paves an effective way toward the designs of high-performance polymer tribo-materials for real engineering uses.