Taking castor oil and polymethylene polyphenyl polyisocyanate(PAPI)as main raw materials,a kind of high thermal conductivity polyurethane potting sealant is prepared through modifying hexahexagonal boron nitride(h-BN),a thermal conductive filler,by KH-550 silane.The influences of modified k-BN on the performance of potting sealant are studied.Results demonstrate that h-BN modification enhances effectively k-BN's dispersibility in polyurethane potting sealant and reduces the viscosity of matrix material.The addition of k-BN improves significantly the thermal conductivity of potting sealant.With a k-BN filling mass fraction of 50％,the thermal conductivity of the prepared sealant is 0.51 W/(m·K),which is 180％higher than that of pure polyurethane.Furthermore,the mechanical property of the prepared sealant is well maintained to meet strength and deformation requirements for potting sealant application.Thermogravimetric analysis reveals an improved thermal stability after k-BN filling.
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