Study On Thermal Conductivity Composite Material Of Boron Nitride/Epoxy Resin Based On Dopamine Modification

Efficient heat dissipation is critical to the performance,life and reliability of modern electronic components and equipment.In recent years,boron nitride?BN?has been favored in the field of insulating and thermally conductive composite materials because of its excellent physical and chemical properties such as high thermal conductivity,high temperature resistance,and oxidation resistance.Generally,unmodified BN is difficult to uniformly disperse into the polymer matrix,which directly affects the performance of the composite material,thus surface modification of BN is essential.First,the excellent surface coating ability of dopamine was used to simultaneously modify the surface of two-dimensional BN and one-dimensional carbon nanotubes?CNTs?in solution.After the modification,CNTs adhered to the surface of BN by polydopamine?PDA?to form an effective heat conduction pathway.Compared with pure epoxy resin?EP?,the addition of 20 vol%m?BN/CNT??10:1?increased the thermal conductivity of epoxy composites by 231%,while maintaining the volume resistivity above 10¹⁴?·cm.Dynamic mechanical analysis?DMA?and scanning electron microscopy?SEM?results showed that PDA functionalization improved the interface interaction between BN,CNT and the epoxy matrix,thereby ensuring improved thermal and mechanical properties of the composites.Secondly,the effects of different proportions of PDA modified BN and two-dimensional graphene nanoplatelets?GNP?as thermal fillers on the thermal conductivity and electrical insulation properties of composites were studied.The results show that the modified BN and GNPs were uniformly dispersed in the epoxy resin;With the addition of 30%of m?BN/GNP?=1:1,the thermal conductivity of the composite material The rate reached 0.61 W/?m·K?,which was an increased by 238.9%compared with pure epoxy matrix,and the composites still maintained excellent insulation properties;Dynamic thermomechanical analysis?DMA?and thermogravimetric analysis?TGA?results showed that the filling of m?BN/GNP?can also improved the thermal stability of epoxy composites.Finally,BN was first modified by dopamine,and then magnetic boron nitride with excellent interfacial compatibility?Fe₃O₄@BN?was successfully synthesized by co-precipitation of Fe₃O₄ onto the surface of BN.The prepared EP/Fe₃O₄@BN composite showed high thermal conductivity and excellent mechanical properties.After the magnetic field alignment,the thermal conductivity of 30 wt%Fe₃O₄@BN filled composites increased from 0.55 W/?m·K?to 0.71 W/?m·K?,which was about 30%higher than the random distributed composites.In addition,Fe₃O₄@BN composites also have excellent storage modulus?5 GPa at 30 wt%?,dielectric properties and insulation properties.Therefore,the EP/Fe₃O₄@BN composite materials have great advantages in the field of electronic packaging.