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2. Molecular simulation of different types of polysilsesquioxane doped cellulose insulating paper: A guide for special cellulose insulating paper.
- Author
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Zeng, Zhenglin, Tan, Weimin, Deng, Yanhe, Cheng, Quan, Fu, Liuyue, and Tang, Chao
- Subjects
- *
CELLULOSE fibers , *CELLULOSE , *GLASS transition temperature , *MODULUS of rigidity , *BULK modulus , *ELASTIC modulus , *DIELECTRIC properties - Abstract
To develop special insulating paper is of great significance to promote the service life of transformers. Using molecular simulation to guide the development of special insulating paper can greatly reduce the trial-and-error rate and waste of resources in traditional experiments. The effect of different types of polysilsesquioxane (POSS) on cellulose insulating paper was investigated by using molecular simulation. This paper investigated the thermal stability and mechanical properties and electrical characteristics of caged POSS, semi-caged POSS, and ladder-like POSS doped cellulose insulating paper. The results show that POSS with all types can enhance the performance of cellulose insulating paper, and ladder-like POSS possess the best modification effect. The glass transition temperature was increased by 58 K, and the bulk modulus, shear modulus, and elastic modulus of cellulose insulating paper doped with ladder-like POSS can improve up to 27.07%, 45.67%, and 41.28%, respectively. Meanwhile, the dielectric properties of ladder-like POSS modified insulating paper are also significantly improved. The findings of this paper propose a method for the preparation of ladder-like POSS modified insulating paper, which provides theoretical guidance for the experimental preparation of special insulating paper. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Fabrication of negative magnetostrictive Japanese traditional paper (washi) with cobalt ferrite particles.
- Author
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Kurita, Hiroki, Rova, Lovisa, Keino, Takumi, and Narita, Fumio
- Subjects
- *
MAGNETOSTRICTION , *FERRITES , *COBALT , *JAPANESE language , *WOOD-pulp , *CELLULOSE fibers , *MAGNETIC particles - Abstract
The cellulose fibers that form washi are longer than those of regular paper made from wood pulp. Hence, the mechanical properties of washi can be higher than those of conventional paper. This study evaluated the magnetic, magnetostrictive, and tensile properties of negative magnetostrictive cobalt ferrite (CoFe2O4) particle dispersed handmade washi (washi−CoFe2O4). The CoFe2O4 additives magnetized the washi, which displayed negative magnetostriction with the fiber direction perpendicular to the magnetic field and in the parallel fiber direction. Concerning the mechanical properties, the washi−CoFe2O4 displayed an elongation of up to 77% after yielding. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Fabrication and characterization of graphene-based paper for heat spreader applications.
- Author
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Muhsan, Ali A. and Lafdi, Khalid
- Subjects
THERMAL conductivity measurement ,THERMAL conductivity ,CHEMICAL processes ,CHEMICAL vapor deposition ,SCANNING electron microscopy ,SLURRY - Abstract
In this work, in-plane thermal conductivity measurement was carried out on graphene-based papers. Graphene-based papers were fabricated using various processing techniques such as chemical vapor deposition (CVD), hot pressing of graphene slurry, and evaporation induced self-assembly. The prepared materials were characterized using scanning electron microscopy, Raman spectroscopy, and X-ray diffraction. In-plane thermal conductivity measurement was performed via a steady state thin film thermal conductivity apparatus. The in-plane thermal conductivity measurements show that the CVD based sample has the highest thermal conductivity. COMSOL Multiphysics was used to simulate the in-plane thermal conductivity of graphene-based papers. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
5. X-ray microtomography and laser ablation in the analysis of ink distribution in coated paper.
- Author
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Myllys, M., Häkkänen, H., Korppi-Tommola, J., Backfolk, K., Sirviö, P., and Timonen, J.
- Subjects
LASER ablation ,X-ray computed microtomography ,INK chemistry ,PERMEABILITY of paper coatings ,PROFILOMETER ,PENETRATION mechanics - Abstract
A novel method was developed for studying the ink-paper interface and the structural variations of a deposited layer of ink. Combining high-resolution x-ray tomography with laser ablation, the depth profile of ink (toner), i.e., its varying thickness, could be determined in a paper substrate. X-ray tomography was used to produce the 3D structure of paper with about 1 μm spatial resolution. Laser ablation combined with optical imaging was used to produce the 3D structure of the printed layer of ink on top of that paper with about 70 nm depth resolution. Ablation depth was calibrated with an optical profilometer. It can be concluded that a toner layer on a light-weight-coated paper substrate was strongly perturbed by protruding fibers of the base paper. Such fibers together with the surface topography of the base paper seem to be the major factors that control the leveling of toner and its penetration into a thinly coated paper substrate. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
6. Electrically and magnetically dual-driven Janus particles for handwriting-enabled electronic paper.
- Author
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Komazaki, Y., Hirama, H., and Torii, T.
- Subjects
- *
JANUS particles , *ELECTRONIC paper , *MICROFLUIDIC analytical techniques , *SUPERPARAMAGNETIC materials , *NANOPARTICLES , *ELECTRIC potential , *MAGNETIC fields , *INTERNET forums - Abstract
In this work, we describe the synthesis of novel electrically and magnetically dual-driven Janus particles for a handwriting-enabled twisting ball display via the microfluidic technique. One hemisphere of the Janus particles contains a charge control agent, which allows the display color to be controlled by applying a voltage and superparamagnetic nanoparticles, allows handwriting by applying a magnetic field to the display. We fabricated a twisting ball display utilizing these Janus particles and tested the electric color control and handwriting using a magnet. As a result, the display was capable of permitting handwriting with a small magnet in addition to conventional color control using an applied voltage (80 V). Handwriting performance was improved by increasing the concentration of superparamagnetic nanoparticles and was determined to be possible even when 80V was applied across the electrodes for 4 wt.% superparamagnetic nanoparticles in one hemisphere. This improvement was impossible when the concentration was reduced to 2 wt.% superparamagnetic nanoparticles. The technology presented in our work can be applied to low-cost, lightweight, highly visible, and energy-saving electronic message boards and large whiteboards because the large-size display can be fabricated easily due to its simple structure. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
7. Reactive molecular dynamics research on influences of water on aging characteristics of PMIA insulation paper.
- Author
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Wang, Lihan, Yin, Fei, Shen, Yin, and Tang, Chao
- Subjects
- *
MOLECULAR dynamics , *INSULATING oils , *CHEMICAL stability , *HYDROXYL group , *ACTIVATION energy , *MOISTURE content of food - Abstract
The diffusion of moisture in the meta-aramid fiber (PMIA) oil-paper insulation system and the thermal decomposition of PMIA insulation paper in different moisture contents were studied via molecular dynamics simulations. The results showed that the PMIA insulation paper had a stronger ability to absorb water molecules than the insulating oil; therefore, water molecules in the insulating oil diffuse to the insulation paper, which further affects the thermal decomposition of the PMIA insulation paper. The activation energy of the water-bearing composite model was 129.96 kJ/mol, which was 5.5% lower than that of the pure PMIA (137.61 kJ/mol). It indicated that moisture could promote PMIA decomposition. The micromechanism of the enhanced thermal decomposition of PMIA with moisture contents could be described as follows: The O–H bond of the water can easily break to generate H atoms and hydroxyl radicals (•OH). The strong activity of H atoms allows it to easily combine with the ammonia base at the end of PMIA to generate NH3. Additionally, the free •OH radical can easily combine with the amido and carbonyl bonds at two ends of PMIA, undergo an oxidation reaction, and generate an oxhydryl. Therefore, it can reduce the chemical stability of the PMIA chain and further drive thermal decomposition. Statistical data on fragments generated by the thermal decomposition of the water-bearing PMIA composite system show that the main products include H2, C/H/O-containing molecules, hydrocarbon molecules, N-bearing molecules, and free radicals. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
8. X-ray texture analysis of paper coating pigments and the correlation with chemical composition analysis.
- Author
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Roine, J., Tenho, M., Murtomaa, M., Lehto, V.-P., and Kansanaho, R.
- Subjects
- *
SURFACES (Technology) , *PRINTING properties of paper , *PRINTING equipment , *X-ray spectroscopy , *SURFACE coatings - Abstract
The present research experiments the applicability of x-ray texture analysis in investigating the properties of paper coatings. The preferred orientations of kaolin, talc, ground calcium carbonate, and precipitated calcium carbonate particles used in four different paper coatings were determined qualitatively based on the measured crystal orientation data. The extent of the orientation, namely, the degree of the texture of each pigment, was characterized quantitatively using a single parameter. As a result, the effect of paper calendering is clearly seen as an increase on the degree of texture of the coating pigments. The effect of calendering on the preferred orientation of kaolin was also evident in an independent energy dispersive spectrometer analysis on micrometer scale and an electron spectroscopy for chemical analysis on nanometer scale. Thus, the present work proves x-ray texture analysis to be a potential research tool for characterizing the properties of paper coating layers. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
9. Improvements of mechanical properties of multilayer open-hole graphene papers.
- Author
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Xia, Yuxuan, Li, Yeyuan, Zhu, Chunhua, Wei, Ning, and Zhao, Junhua
- Subjects
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SHEAR strength , *CARBON-carbon bonds , *TENSILE strength , *STRESS concentration , *COVALENT bonds , *LAMINATED glass - Abstract
Holes and defects can greatly reduce the mechanical properties of multilayer graphene sheets under different loading conditions due to the stress concentration near the hole edge in each in-plane sheet and the lack of interlayer carbon–carbon bonds between the layers. Here, we report a novel design of multilayer open-hole graphene papers (MLGPs) formed through interlayer covalent bonding at the hole edges of multilayer open-hole graphene sheets (MLGSs) under high temperature using molecular dynamics (MD) simulations. Our MD results show that the hybrid sp2–sp3 interlayer bonds of MLGPs can significantly improve their both tensile strength and interlayer shear strength. The tensile strength and interlayer shear strength of MLGPs increase by around 20% and 3 times by comparison with those of MLGSs with the same number of layers, respectively, which mainly depends on the uniformity of their interlayer bond distribution. This study can provide an effective way to improve the mechanical performances of multilayer graphene sheets with flaws and also offer corresponding guidance for the design of MLGS-based nanocomposites. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
10. Thin film versus paper-like reduced graphene oxide: Comparative study of structural, electrical, and thermoelectrical properties.
- Author
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Okhay, Olena, Gonçalves, Gil, Tkach, Alexander, Dias, Catarina, Ventura, Joao, da Silva, Manuel Fernando Ribeiro, Valente Gonçalves, Luís Miguel, and Titus, Elby
- Subjects
GRAPHENE oxide ,THIN films ,CHEMICAL reduction ,HYDRAZINE ,SEMICONDUCTORS - Abstract
We report fabrication of reduced graphene oxide (rGO) films using chemical reduction by hydrazine hydrate and rGO paper-like samples using low temperature treatment reduction. Structural analysis confirms the formation of the rGO structure for both samples. Current-voltage (I-V) measurements of the rGO film reveal semiconductor behavior with the maximum current value of ~3×10
-4 A. The current for the rGO paper sample is found to be, at least, one order of magnitude higher. Moreover, bipolar resistance switching, corresponding to memristive behavior of type II, is observed in the I-V data of the rGO paper. Although precise values of the rGO film conductivity and the Seebeck coefficient could not be measured, rGO paper shows an electrical conductivity of 6.7×102 S/m and Seebeck coefficient of -6μV/°C. Thus, we demonstrate a simplified way for the fabrication of rGO paper that possesses better and easier measurable macroscopic electrical properties than that of rGO thin film. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
- View/download PDF
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