Effect of doped nano-SiO2, Al2O3, and polyhedral oligomeric sesquisiloxane on the thermodynamic properties of cellulose

Abstract

Cellulose insulation paper is an essential part of the transformer oil-paper insulation system, and many types of nano-modified insulating paper are available. For studying the effects of various nano-modified molecules on cellulose and the differences in performance, the pure cellulose model and polyoctaaminophenylsesquioxane and grafted 3-aminopropyltriethoxysilane (KH550) SiO2 and Al2O3 cellulose models were developed using molecular dynamics methods, and the mechanical properties and thermally stability were calculated and compared. The findings show that, in general, all three nano-modification models improved the thermal stability and mechanical properties, with nano-SiO2-KH550 cellulose having the best overall modification effect. In terms of mechanical properties, the nano-SiO2-KH550 cellulose showed the largest increase in compressive strength, with an 18.1% improvement. In terms of thermal stability, the KH550 grafted nano-silica/cellulose composite model showed the best modification effect, as evidenced by the smaller cohesive energy density and free volume region compressing the space between cellulose molecules, making the modified cellulose more compact internally, thus achieving the effect of inhibiting the movement of cellulose chains.