High Mechanical and Thermal Performance of Insulating Paper Cellulose Modified with Appropriate h‐BN Doping Amount: A Molecular Simulation Study

Abstract

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.

Molecular simulation on the mechanical and thermal properties of modified insulating paper cellulose doped with trapezoidal polyphenylsesquisiloxane at different temperature

“…For the constructed models, optimization methods like geometry optimization, anneal and dynamics are required to ensure that the model energy is at the minimum and the geometry is at the most stable state, which is closer to the characteristics of real materials and can truly reflect and predict the properties of real materials. The model first needs to carry out 30,000 steps of geometry optimization under the COMPASS force field, 27,28 then carry out 10 cycles of Annealing treatment under the ensemble of NVT and the temperature of 300 K $ 900 K, and finally successively carry out the dynamic optimization with the ensemble of NPT, NVT, and NPT, the pressure of 1 and 0.0001 GPa and the time of 500 ps. Based on the optimized model, the relevant performance parameters of the model can be calculated.…”

Ladderlike Polyphenylsesquioxane‐Doped Cellulose Insulation Paper with Upgraded Mechanical Strength

“…And then, the model was annealed in the temperature range of 300-900 K, in cycles of 50 K, to ensure that the model density was stabilized at around 1.37 g cm À3 . [16,19,35] Finally, four dynamics simulations are performed on the model with a force field of COMPASS II, [36,38] which is the most suitable force field for cellulose. The temperature control method used for the molecular simulation in this study is the nose method and the pressure control method is the Berendsen method.…”

Microscopic Mechanism of Electrical Aging of PVDF Cable Insulation Material

“…With the rapid development of computer technology and software engineering, many previous experiments can be further studied at the microscopic level. The theory of quantum mechanics means that molecular simulation technology is not only limited to the study of chemistry, but also extended to electrical, physical, biological and material science and other disciplines, promoting the development of interdisciplinary research and providing a new means for people to understand the material world, in addition to experimental methods and theoretical methods [15]. Many scholars have applied molecular simulation methods to the field of high-voltage insulation, such as the synergistic effect of electric fields and temperature on insulating oil [16,17], the microscopic mechanism of the overheating of insulating oil [18,19], the aging and degradation of insulating materials [20,21], and the diffusion of gas molecules in oil paper insulation systems [22,23].…”