Waterborne polyurethane (WPU) is attracting widespread attention in the friction field, but pure WPU cannot meet the wear resistance requirements due to poor thermal and self-lubricating properties. Herein, a novel cellulose/BNNSs-AgNPs aerogel (CBAg) composed of zero-dimensional silver nanoparticles (AgNPs), one-dimensional cellulose and two-dimensional boron nitride nanosheets (BNNSs) was successfully fabricated. Specifically, AgNPs were loaded onto the surface of BNNSs, which could serve as bridges to connect adjacent BNNSs. Cellulose was used to construct a 3D skeleton structure for stabilizing better dispersion of inorganic fillers. Finally, the thermal and tribological properties of CBAg-WPU were improved compared to pure WPU, with a 69% increase in thermal conductivity and an 89% reduction in wear rate. This was attributed to the load-bearing capacity of cellulose and outstanding thermal and lubricant capability of BNNSs-AgNPs. In addition, BNNSs and AgNPs inside the aerogel were transferred to the sliding interface and participated in the formation of high-quality friction transfer film, further endowing CBAg-WPU composites prominent tribological performance. Therefore, the novel design of 3D hybrid aerogels provided a promising avenue to improve the tribological performance of WPU composites.

Epoxy resin (EP) composites with satisfactory thermal and tribological performance are highly required for engineering moving components. However, the simple addition of fillers leaded to the serious filler agglomeration and limited promotion in tribological properties. In this work, we constructed a new kind of three-dimensional (3D) reduced graphene oxide (RGO)/Si₃N₄ hybrid aerogel for EP composites, which was prepared by a facile hydrothermal self-assembly method followed by freeze-drying technique. As a result, the dispersibility of Si₃N₄ whiskers was greatly improved through wrapping of polydopamine–polyethyleneimine copolymer (PDA–PEI) copolymer and physical spacing of 3D skeleton. Furthermore, benefiting from the synergistic effect of RGO and Si₃N₄@PDA–PEI in the thermal network, the thermal conductivity of RGO/Si₃N₄ hybrid aerogel (GSiA)–EP increased by 45.4% compared to that of the neat EP. In addition, the friction coefficient and wear rate of GSiA–EP decreased by 83.7% and 35.8%, respectively. This work is significant for opening a tribological performance enhancement strategy though constructing 3D hybrid architecture.