Polyethylene glycol covalently modified the corroded hexagonal boron nitride to improve the thermal conductivity of epoxy composites

The wide application of hexagonal boron nitride (h-BN) is limited because it is difficult to achieve functionalization with trace amounts of active groups. We noticed that a considerable amount of hydroxyl and amino groups are generated after mixing h-BN and sulfonyl chloride at room temperature for 48 h. Subsequently, these active groups are used to react with furoyl chloride, and polyethylene glycol (PEG) is introduced through a mild DielsAlder reaction to improve its dispersibility and compatibility with epoxy resin matrix. The modified h-BN are characterized by Fourier transform infrared (FT-IR), thermogravimetric (TGA), and transmission electron microscopy (TEM) to investigate the covalent modification results and its structure. Finally, the thermal conductivity of epoxy composites with different filler content show that the h-BN covalently modified by PEG can improve the thermal conductivity of the composites.