With the improvement of operation requirements of power equipment, the stable operation of insulation of equipment is very important. Among them, insulating paper is one of the main factors affecting the state of equipment. Therefore, it is important to improve the performance of insulating paper. The pure cellulose model and h‐BN/cellulose composite model are established to analyze the improvement of thermal and mechanical properties of insulating paper cellulose. The effects of different contents of h‐BN doping on the properties of cellulose are studied by comparing the mechanical parameters, cohesive energy density, thermal conductivity, mean square displacement, and free volume of cellulose before and after h‐BN doping through molecular dynamics method. The results indicate that the thermal conductivity and thermal stability of cellulose are improved by more than 15% at the h‐BN mass fraction of 2% and 3%, the shear modulus and elastic modulus are enhanced by more than 50%, and the deformation resistance and ductility of the composites are enhanced when the mass fraction of h‐BN is 2%. The doping of h‐BN has an important impact on improving the thermodynamic properties of cellulose, which is of great significance to improving the insulation performance of power equipment and reducing equipment faults.

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Ladderlike polyphenylsesquioxane (L‐PPSQ) with special planar ladder structure is significant to upgrade the mechanical strength of cellulose insulation paper. In this study, the effect of different content of L‐PPSQ on mechanical properties and dielectric properties of cellulose is first investigated by molecular simulation, and then insulation paper doped with L‐PPSQ is prepared for experimental verification. It is indicated in the simulation results that the elastic modulus, bulk modulus, and shear modulus of the cellulose are enhanced up to 36.82%, 27.96%, and 41.80%, respectively, when L‐PPSQ is added at 3 wt%, and the cellulose model with 3 wt% L‐PPSQ possesses the lowest dielectric constant. The reason is that L‐PPSQ can enhance the hydrogen bonding network of cellulose, weaken the degree of molecular chain motion, and strengthen the strength of molecular chains, which in turn manifests as the enhancement of mechanical strength. It is shown in the experimental results that the tensile strength and elongation at break of the composite insulation paper can be enhanced by 16.7% and 35.09% when the L‐PPSQ content is 3 wt%, which is consistent with the simulation results. The short‐term aging test shows that L‐PPSQ can also upgrade the mechanical strength of the insulation paper at high temperatures.

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