Thermal Stability of Modified Insulation Paper Cellulose Based on Molecular Dynamics Simulation

Tang, Chao; Zhang, Song; Wang, Qian; Wang, Xiaobo; Hao, Jian

doi:10.3390/en10030397

Cited by 15 publications

(11 citation statements)

References 19 publications

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“…To determine the variation of the mechanical properties and solubility of the cellulose chain, models of 19 groups of single cellulose chains in the amorphous region with the polymerization degrees of 2,4,6,8,9,10,12,16,20,25,30,35,40,50,60,70,80,90, and 100 were constructed using COMPASS and PCFF force fields. The model density obtained by W. Chen [21] was about 1.385 g/cm 3 , while K. Mazeau and L. Heux [11] achieved a model with four different densities of 1.34-1.3927 g/cm 3 by modeling with the same method and standpoint, and proposed that the density of cellulose in the amorphous region is 1.28-1.44 g/cm 3 .…”

Section: Models Buildingmentioning

confidence: 99%

Selection of Optimal Polymerization Degree and Force Field in the Molecular Dynamics Simulation of Insulating Paper Cellulose

Wang

Tang

Wang³

et al. 2017

Energies

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Abstract:To study the microscopic thermal aging mechanism of insulating paper cellulose through molecular dynamics simulation, it is important to select suitable DP (Degree of Polymerization) and force field for the cellulose model to shorten the simulation time and obtain correct and objective simulation results. Here, the variation of the mechanical properties and solubility parameters of models with different polymerization degrees and force fields were analyzed. Numerous cellulose models with different polymerization degrees were constructed to determine the relative optimal force field from the perspectives of the similarity of the density of cellulose models in equilibrium to the actual cellulose density, and the volatility and repeatability of the mechanical properties of the models through the selection of a stable polymerization degree using the two force fields. The results showed that when the polymerization degree was more than or equal to 10, the mechanical properties and solubility of cellulose models with the COMPASS (Condensed-phase Optimized Molecular Potential for Atomistic Simulation Studies) and PCFF (Polymer Consistent Force Field) force fields were in steady states. The steady-state density of the cellulose model using the COMPASS force field was closer to the actual density of cellulose. Thus, the COMPASS force field is favorable for molecular dynamics simulation of amorphous cellulose.

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Section: Models Buildingmentioning

confidence: 99%

Selection of Optimal Polymerization Degree and Force Field in the Molecular Dynamics Simulation of Insulating Paper Cellulose

Wang

Tang

Wang³

et al. 2017

Energies

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“…In recent years, numerous studies have focused on the thermal aging mechanism of insulation paper. Although the aging process and its mechanism on oil–paper in transformers have been investigated [8,9,10,11,12,13,14,15,16,17,18], the thermal stability of meta-aramid insulation paper in transformers at operating temperature has not been analyzed. Therefore, it remains important to examine the thermal stability and thermal aging mechanism of crystalline and amorphous regions in meta-aramid insulation paper.…”

Section: Introductionmentioning

confidence: 99%

Molecular Simulation on the Thermal Stability of Meta-Aramid Insulation Paper Fiber at Transformer Operating Temperature

Tang

et al. 2018

Polymers

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The influence of the thermal field of a transformer during operation on the thermal stability of meta-aramid insulation paper was studied through molecular dynamics simulations. Models of the crystalline and amorphous regions of meta-aramid fibers were constructed using known parameters. The model of the crystalline area was verified by comparing X-ray diffraction results with experimental data. The reasonableness of the simulation results was judged by the variation of energy, temperature, density, and cell size in relation to the dynamic time. The molecular dynamics simulations revealed that the modulus values in the crystalline regions were two to three times higher than those in the amorphous regions at various temperatures. In addition, the incompressibility, rigidity, deformation resistance, plasticity, and toughness of the crystalline regions were obviously higher than those of amorphous regions, whereas the toughness of the amorphous regions was better than that of the crystalline regions. The mechanical parameters of both the crystalline and amorphous regions of meta-aramid fibers were affected by temperature, although the amorphous regions were more sensitive to temperature than the crystalline regions. The molecular chain motion in the crystalline regions of meta-aramid fibers increased slightly with temperature, whereas that of the amorphous regions was more sensitive to temperature. Analyzing hydrogen bonding revealed that long-term operation at high temperature may destroy the structure of the crystalline regions of meta-aramid fibers, degrading the performance of meta-aramid insulation paper. Therefore, increasing the crystallinity and lowering the transformer operating temperature may improve the thermal stability of meta-aramid insulation paper. However, it should be noted that increasing the crystallinity of insulation paper may lower its toughness. These study results lay a good foundation for further exploration of the ways to improve the performance of meta-aramid insulation paper.

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“…Diffraction pattern for new kraft paper has two different peaks at 2 = 15.57 0 and 2 = 22.29 0 , which indicated the diffraction of the crystalline structure. By interpreting the diffractograph, some of parameters such as crystal size (D) and relative crystallinity (Crel) can be measured [18]. Relative crystallinity of the kraft paper is calculated by using equation 2 [17]:…”

Section: B X-ray Diffraction Analysismentioning

confidence: 99%

“…The peak positions are around 2 = 15.57 0 and 2 = 22.29 0 . It indicates that during accelerated thermal aging, the crystal type has not changed [18]. By using equation (2), the relative crystallinity of kraft paper can be calculated.…”

Section: B X-ray Diffraction Analysismentioning

confidence: 99%

Comparative Study of Kraft Paper Aged in Natural Ester with XRD and TG/DTG Analysis

Sari¹,

Ritonga²,

Suwarno³

2019

ijeei

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High voltage transformer is an essential electrical equipment that determine the reliability and continuity of power system. Basically, it consists of solid and liquid insulating materials. Kraft paper as solid insulation should have an ability to insulate the winding connection, while oil transformer, aside of its main function as an insulation, it is essential to provide cooling mechanism. This paper analyzes the accelerated thermal aging performance of kraft paper immersed in the natural ester from RBD palm oil by using X-Ray Diffraction (XRD) characterization and thermogravimetric analysis. XRD characterization was used to determine the existence of crystalline structure in kraft paper. Crystalline structure in kraft paper is composed by cellulose. The toughness of kraft paper was determined by its amorphous region, lignin, that bind the cellulose and make them hard. The influence of thermal expansion was observed to discover the effect of thermal stress to the crystallinity of kraft paper. Besides, thermal degradation characteristics of kraft paper were examined by using thermogravimetric analysis. The sample was aged in 120 0 C and 150 0 C for two weeks. The results also show that crystalline region of the sample that heated in higher aging temperature tends to drop faster than the sample with lower aging temperature.

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Thermal Stability of Modified Insulation Paper Cellulose Based on Molecular Dynamics Simulation

Cited by 15 publications

References 19 publications

Selection of Optimal Polymerization Degree and Force Field in the Molecular Dynamics Simulation of Insulating Paper Cellulose

Selection of Optimal Polymerization Degree and Force Field in the Molecular Dynamics Simulation of Insulating Paper Cellulose

Molecular Simulation on the Thermal Stability of Meta-Aramid Insulation Paper Fiber at Transformer Operating Temperature

Comparative Study of Kraft Paper Aged in Natural Ester with XRD and TG/DTG Analysis

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