Cellulose-Based Nanocomposite Insulation Material with Excellent Thermal Aging Resistance: KH550-hBN-Modified Cellulose Insulation Paper

As the global power industry evolves, transformer insulation systems face increasing challenges. The aging of cellulose insulation paper (cellulose-IP) at elevated temperatures significantly impacts its insulation properties and overall lifespan. To enhance the thermal aging resistance and industrial usability of cellulose-IP, this study employs nano-boron nitride (h-BN) along with three silane coupling agents—3-ammonopropyltriethoxysilane (KH550), 3-glycidyloxypropyltrimethoxysilane (KH560), and 3-methacryloyloxypropyltrimethoxysilane (KH570)—to modified cellulose-IP. Upon evaluating the properties and simulation results of the modified cellulose-IP, KH550-hBN demonstrated superior properties and was selected for an accelerated thermal aging test lasting 60 days. The results indicated that KH550-hBN effectively mitigates the degradation of cellulose-IP. In the late aging stage, the mechanical properties of the modified cellulose-IP deteriorated more slowly than those of pure cellulose-IP. Additionally, thermal conductivity improved by 26.9%, while breakdown field strength increased by 12.1%. The introduction of KH550-hBN promotes the formation of a complete thermal conductivity network within the cellulose matrix, increases the number of intermolecular hydrogen bonds and introduces nano-barrier regions.These improvements enhance the interactions between the cellulose systems and effectively inhibit the generation and migration of polar derivatives during the aging process, resulting in a significant improvement in the longevity and stability of transformer internal insulation systems.