Thermal stability of epoxy nanocomposites: surface treatment and morphology impact based on nano SiO₂ and hBN fillers

Epoxy resin is one of the most commonly used thermosetting macromolecular synthetic materials. It displays excellent adhesiveness properties, good dielectric property, mechanical property and chemical stability. Consequently, epoxy resins have been widely used for many industrial purposes, such as electrical casting into power transformers, ignition coil systems and potting. In this paper, TGA and DSC measurements were carried out to evaluate the thermal stability of epoxy nanocomposites. Based on the results of dispersion and distribution of particles within epoxy nanocomposites, it concluded that both presences of nano SiO 2 and hexagonal BN (hBN) particles have obvious impact on base materials in which the influences of latter particle are much more significant due to its shape, and thus both fillers leads to worse thermal stability than pure samples. However, particles could act as flame retardants in polymer nanocomposites and postpone the initiation of decomposition by hindering/slowing the oxidisation. When compared within two SiO 2 based nanocomposites, the surface treatment seems to help mitigate the influences on base materials by achieving better filler dispersion and modify the cross-linking density at the interfacial areas by removing surface functional groups.