Preparation And Properties Of Insulating Thermal Conductive Cyanate Ester Based Composites

The coupling agent (KH550) was selected to treat tetrapod-like zinc oxide whiskers (T-ZnOw) and hexagonal boron nitride (h-BN) powders, and the dodecylamine (DDA) was used to improve the hydrophobicity of graphite oxide. The structure and morphology of the products were investigated by Fourier-Transform Infrared Spectrography (FT-IR), X-ray diffraction (XRD), Nuclear Magnetic Resonance Spectroscopy (NMR), Thermal Gravity Analysis (TG), Scanning Electronic Microscopy (SEM) and Transmission Electronic Microscopy (TEM). The results indicate that KH550 and DDA have been grafted to the surface of the inorganic particles successfully, and the surface treatment is beneficial to the dispersion of fillers in the resin system.The modified T-ZnOw, h-BN and GO-DDA were respectively incorporated into the cyanate ester (CE) resin system. Four kinds of insulating and thermal conductive composites were prepared based on CE resins, such as ZnOw/CE, BN/CE, BN-ZnOw/CE and GO-DDA/CE. The thermal conductive tester, high resistance meter, high-frequency Q meter, Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), SEM and TG were used to determine the properties of composites. The effects of the kind and content of fillers on the thermal conductivity, electrical insulation, fracture toughness, thermal stability and dynamic mechanical properties were discussed in detail. The results show that the addition of three kinds of fillers can all improve the thermal conductivity of composites. Especially, the thermal conductivity of the composites with hybrid ZnO whisker and BN particles is higher than that of single BN filler at the same loading. All composites remain good electrical insulation properties, expect for GO-DDA/CE composite, which shows poor electrical insulation properties when the GO-DDA content is high. Besides, the addition of three kinds of fillers can all promote the curing of CE resins and also can improve the fracture toughness and thermal stability of the composites. At the same time, the effect of the hybrid filler content on dynamic mechanical property of BN-ZnOw/CE composites was investigated. The results indicate that the storage modulus of composites increases with the enhancement of BN-ZnOw hybrid filler content. In addition, the hybrid filler content can reduce the glass transform temperature (Tg).