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 hexagonal boron nitride (h-BN) along with three silane coupling agents (SCAs)—3-ammonopropyl- triethoxysilane (KH550), 3-glycidyloxypropyltrimethoxysi- lane (KH560), and 3-methacryloyloxypropyltrimethoxysilane (KH570)—to modified cellulose-IP. Upon evaluating the properties and simulation results of the modified cellulose-IP, KH550-hBN demonstrates superior properties and is selected for an accelerated thermal aging test lasting 60 days. The results indicate that KH550-hBN effectively mitigates the degradation of cellulose-IP. In the late aging stage, the mechanical properties of the modified cellulose-IP deteriorate more slowly than those of pure cellulose-IP. Additionally, thermal conductivity (TC) improves by 26.9%, while breakdown field strength increases by 12.1%. The introduction of KH550-hBN promotes the formation of a complete TC network within the cellulose matrix, increases the number of intermolecular hydrogen bonds, and introduces nanobarrier 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.