Tannic acid/polyethyleneimine functionalized hexagonal boron nitride: Enhancing tribological properties of epoxy-based composite coatings

The interfacial compatibility issue of boron nitride (BN) nanofillers in epoxy resin (EP) matrix is one of the major challenges plaguing the efficient application of composites. Herein, inspired by phenol-amine green chemistry, microwave-assisted ball milling was used to synthesize tannic acid (TA) and polyethyleneimine (PEI) functionalized boron nitride (TA/PEI@BN). Characterization indicated that TA/PEI grafted on BN via both non-covalent and covalent interactions, which improved the interfacial compatibility and cross-linking properties of TA/PEI@BN within the EP. Meanwhile, the introduction of 0.25 % TA/PEI@BN reduced the average friction coefficient and wear rate of the EP composite coating by 17 % and 50 %, respectively. The characterization of the friction interface showed that TA/PEI@BN could exhibit a "sliding complementary repair" effect during friction. This work presents a novel, green, and scalable method for realizing the surface functionalization of BN, beneficial for the further application of high-performance epoxy matrix composites.