The performance of the epoxy/hybrid nanofiller composites was evaluated in terms of thermal conductivity and stability. The thermal stability of the composites was determined by TGA experiments under an inert atmosphere as discussed in the experimental details. The TGA curves of the pristine epoxy and hybrid filler/epoxy composites showed similar thermal degradation trends around 395 C matches with literature , as shown in Figure . The addition of BNNS and BNNT slightly improves the thermal stability of the composite and retards the thermal degradation process up to 2-3% and the higher the filler content, the better the thermal stability. The improvement in thermal stability of the composite is mainly attributed to the fact that the BNNS and BNNT, which are uniformly dispersed in the epoxy, act as a heat-resistant layer and mass transfer barrier to hinder the thermal degradation process. 18 To investigate the effect on the thermal conductivity, Figure compares the thermal conductivities of the composites containing BNNS and BNNT as a function of filler loadings.