Protruding Boron\nNitride Nanotubes on the Al<sub>2</sub>O<sub>3</sub> Surface Enabled\nby Tannic Acid-Assisted Modification\nto Fabricate a Thermal Conductive Epoxy/Al<sub>2</sub>O<sub>3</sub> Composit

Over the past few years, the ability to efficiently increase\nboron\nnitride nanotube (BNNT) production has opened up ample research possibilities.\nBNNT has garnered significant attention for diversifying its industrial\napplications. However, the problem of poor processability resulting\nfrom agglomeration and uneven distribution has emerged as a major\nchallenge to integrating BNNT into the polymer matrix for composite\nmaterial formation. Utilizing noncovalently attached molecules with\nvarious reactive sites can be a logical method to enhance the compatibility\nof BNNT with different polymers. The present study explored a simple\napproach to protruding BNNT onto the surface of Al<sub>2</sub>O<sub>3</sub> through tannic acid (TA)-assisted generation of alkyl chains\n(octadecylamine, ODA) to fabricate Al<sub>2</sub>O<sub>3</sub>@ODA-BNNT.\nThe subsequent compounding of Al<sub>2</sub>O<sub>3</sub>@ODA-BNNT\nwith epoxy polymer generates interconnected thermal conduction pathways,\nthereby improving the thermal conduction and mechanical performance\nof the composites. The current research approach allows for the even\ndistribution of BNNT throughout the polymer matrix, as demonstrated\nby optical characterization, mechanical performance analysis, and\nisotropic thermal conductivity analysis. The fabricated epoxy composite\nby incorporating a 2 wt % (BNNT = 1.3 wt % and ODA = 0.7 wt %) ODA-BNNT\nexhibited 5.117 W/mK thermal conductivity and 7.43 MPa mechanical\nstress. Thermal conductivity improved by 2528, 76.56, and 54.7%, while\nmechanical stress enhanced by 270, 221, and 34% compared to neat polymers\nwithout BNNT and virgin BNNT epoxy composites, respectively.