Aging of Transformer Insulation Paper

Abstract

As a transformer ages, the chemical and physical properties of the cellulose insulation materials in the transformer change, and the paper loses its strength and becomes brittle. The average molecular weight of the cellulose chains decrease with age, and degradation products are formed, including water, carbon monoxide, carbon dioxide, and furans. The molecular weight changes in the cellulose have been studied by several methods, but the GPC method for determination of the molecular weight has been shown to offer advantages over other methods because it yields the total molecular weight distribution. The tensile strength of the cellulose insulation in transformers also changes with age as a result of the changing molecular weight of the cellulose. Work carried out in our laboratory on the aging of cellulose insulation is reviewed in this paper. Our studies have included investigations of insulation materials from retired transformers as well as accelerated aging of insulation paper in transformer oil in the temperature range of 129–166°C under vacuum. In the study the relationships between the molecular weight of the cellulose and the furan degradation products and tensile strength have been delineated, and they have been correlated with information on the kinetics of degradation of the insulation paper.     

Development of Paper Actuators Based on Carbon-Nanotube-Composite Paper

We propose a unique soft actuator—a paper actuator—based on carbon-nanotube-composite paper (CNT-composite paper), which is a composite of carbon nanotubes (CNTs) and paper. CNT-composite paper has highly efficient properties because of the contained CNTs, such as high electrical conductivity and semiconducting properties. We are considering using CNT-composite paper for various devices. In this study, we successfully developed a paper actuator. We determined the structure of the paper actuator by referencing that of bucky-gel actuators. The actuator operates using the force generated by the movement of ions. In addition to making the paper actuator, we also attempted to improve its performance, using pressure as an index and an electronic scale to measure the pressure. We investigated the optimal dispersant for use in paper actuators, expecting the residual dispersant on the CNT-composite paper to affect the performance differently depending on the type of dispersant. Referring to research on bucky-gel actuators, we also found that the addition of carbon powder to the electrode layers is effective in improving the pressure for paper actuators. We believe that the paper actuator could be used in various situations due to its ease of processing.     

基于天然聚多糖的环境友好材料（II）-麻纤维和芦苇纤维多元醇的生物降解聚氨酯

以麻纤维和芦苇纤维制备的植物多元醇为原料,合成具有良好性能的生物降解 性硬质聚氨酯泡沫体,其密度40 kg/m~3左右,压缩强度150 kPa,弹性模量4 MPa 。而且多元醇中植物原料含量越大,其性能越好,这使植物原料的充分利用和材料 生产成本的降低成为可能。土壤掩埋实验表明,泡沫体有很好的土壤微生物降解性 。     

Thermoanalytical Contribution to the Study on Paper Degradation. Characterisation of Oxidised Paper

In this paper we studied the effect of oxidation on paper stability by means of simultaneous differential thermal analysis and thermogravimetry. In our laboratory we oxidised Whatman n. 1 chromatography grade paper and performed thermal analyses both on non-oxidised and on 6, 21 and 96 h oxidised samples. The results showed characteristic thermal effects, particularly performing the experiments under oxygen flow: it was noticed that the temperature of the main cellulose degradation DTA peak gradually decreases with the paper oxidation degree. An application of this method was extended to the study of differently oxidised parts of a 1948's book. This revised version was published online in July 2006 with corrections to the Cover Date.     

亚铈试纸的设计与制作

以中速定量滤纸作为基纸,依次用作为基纸改性剂的十六烷基三甲基溴化铵(质量分数0.5%)和作为显色剂的二甲酚橙(质量分数0.2%)浸泡、晾干,制成亚铈试纸。 用1.000×10^-5~1.000 mol/L的Ce³⁺标准溶液分别浸泡该试纸,制成11种颜色的标准比色卡。 建立了强酸性Ce⁴⁺/Ce³⁺混合液中Ce³⁺浓度的半定量试纸测定法。 将本法应用于再生电解液和模拟有机合成液中Ce³⁺ 浓度的测定,表明只需用质量分数20%的六次甲基四胺缓冲溶液将试液调整至pH值5.0~6.0,结果准确度良好,共存的Ce⁴⁺、对苯二酚、对羟基苯甲醛、1,10-二羟基蒽醌等组分均不产生干扰。 该试纸具有制作方法简单、廉价易得、检测快速、易操作等优点,可应用于生产流程中Ce³⁺浓度的快速检测。     

Synthetic Paper

Synthetic paper can be made either by forming a web from synthetic fibers or by extruding a film from thermoplastic polymers. With suitable starting materials and appropriate treatment it is possible to equal the properties of conventional cellulose paper; in some respects, as in wet strength and dimensional stability, the synthetic papers are clearly superior.     

Stability of Alum-Containing Paper under Alkaline Conditions

The present contribution evaluates the methods of degradation and stabilization of alum-containing paper with a focus on the alkaline environment achieved by deacidification procedures. In terms of reviewed subjects, the contribution focuses on alum-rosin sized paper, which is still used as a carrier of knowledge and information; however, it also mentions cellulose itself and other brands of paper. The contribution summarizes the results on the homogeneity of the distribution of alum and rosin in the paper mass and on the paper surface. It provides the knowledge gained in the field of alkaline hydrolysis and oxidation with special regard to transition metal species. It shows the values of alkaline reserves achieved in the main mass-deacidification processes. On the basis of the acquired knowledge, the contribution emphasizes the procedures of paper stabilization. Criteria of “increased mechanical permanence and lifetime prolongation” adopted to evaluate and compare the efficacy of individual mass-deacidification processes were applied and corresponding data are introduced. The contribution also draws attention to the existence of open issues in the area of paper degradation and stabilization.     

电化学还原处理对碳纸形貌和电化学电容的影响

对电化学还原处理过程中碳纸的形貌和电容的变化进行了研究. 扫描电子显微镜观测结果显示电还原使碳纤维分解为碳颗粒, 并且表面粗糙度增加. 拉曼光谱结果显示I_D/I_G的比值在还原处理1 min后即出现改变, 表明碳纸无序度增加. BET测试结果显示电还原处理后碳纸的比表面积明显增加. X射线光电子能谱结果表明还原处理后碳纸表面羟基的数量随之增加. 此外, 在-1.6 V下还原5 min后碳纸电容增加到原来的15倍, 并在1500个循环的稳定性测试中保持不变, 显示出良好的稳定性.     

纸基过氯乙烯树脂微流控亚硝酸根离子检测片的研制

基于滤纸上过氯乙烯树脂栏选择性通过亚硝酸根离子, 结合微流控分析装置设计, 研制成纸基过氯乙烯树脂微流控亚硝酸根离子检测芯片. 采用该微流控亚硝酸根离子检测芯片测定了亚硝酸盐样品, 线性范围和检测限分别为70～1500 μmol/L 和48 μmol/L. 该微流控亚硝酸根离子检测芯片已成功应用于水样和食品中亚硝酸盐测定, 结果满意.     

Flexible Polyester Cellulose Paper Supercapacitor with a Gel Electrolyte

A low-cost polyester cellulose paper has been used as a substrate for a flexible supercapacitor device that contains aqueous carbon nanotube ink as the electrodes and a polyvinyl alcohol (PVA)-based gel as the electrolyte. Gel electrolytes have attracted much interest due to their solvent-holding capacity and good film-forming capability. The electrodes are characterized for their conductivity and morphology. Because of its high conductivity, the conductive paper is studied in supercapacitor applications as active electrodes and as separators after coating with polyvinylidene fluoride. Carbon nanotubes deposited on porous paper are more accessible to ions in the electrolyte than those on flat substrates, which results in higher power density. A simple fabrication process is achieved and paper supercapacitors are tested for their performance in both aqueous and PVA gel electrolytes by using galvanostatic and cyclic voltammetry methods. A high specific capacitance of 270 F g⁻¹ and an energy density value of 37 W h kg⁻¹ are achieved for devices with PVA gel electrolytes. Furthermore, this device can maintain excellent specific capacitance even under high currents. This is also confirmed by another counter experiment with aqueous sulfuric acid as the electrolyte. The cycle life, one of the most critical parameters in supercapacitor operations, is found to be excellent (6000 cycles) and less than 0.5 % capacitance loss is observed. Moreover, the supercapacitor device is flexible and even after twisting does not show any cracks or evidence of breakage, and shows almost the same specific capacitance of 267 F g⁻¹and energy density of 37 W h kg⁻¹. This work suggests that a paper substrate can be a highly scalable and low-cost solution for high-performance supercapacitors.     

以硅胶G胶片和滤纸作基质氟哌酸的固体基质室温燐光法研究

探讨了氟哌酸的固体基质室温燐光法（ＳＳ－ＲＴＰ）中的基质效应和重原于效应，经聚丙烯酸（ＰＡＡ）处理的硅胶Ｇ胶片做基质测定痕量氟哌酸较滤纸为基质具有检测限低、无需重原子微扰剂，稳定性好等优点。     

A Self-supporting,Surface Carbonized Filter Paper Membrane for Efficient Water-in-Oil Emulsion Separation

Due to the important role of oil source in our life, the separation of water-in-oil emulsion is urgent and necessary. Membrane seperation technology has been an efficient and widely used method in separating oil-water separation. Herein, we report a versatile approach to fabricate surface carbonized membranes with self-standing property from biomass-derived precursor by synergistic charring of phytic acid,arginine and filter paper. The obtained membrane exhibited superhydrophobicity in oil, excellent fouling resistance, and self-supporting ability.The membrane can be cycle-used at least 12 times with high permeation flux(up to 1380 L·m~(-2)·h~(-1)) and separation efficiency(up to 99.4%).     

Wet End Chemical Properties of a New Kind of Fire-Resistant Paper Pulp Based on Ultralong Hydroxyapatite Nanowires

In 2014, a new type of the fire-resistant paper based on ultralong hydroxyapatite (HAP) nanowires was reported by the author’s research group, which had superior properties and promising applications in various fields, such as high-temperature resistance, fire retardance, heat insulation, electrical insulation, energy, environmental protection, and biomedicine. The wet end chemical properties of the fire-resistant paper pulp are very important for papermaking and mechanical performance of the paper, which play a guiding role in the practical production of the fire-resistant paper. In this paper, the wet end chemical properties of a new kind of fire-resistant paper pulp based on ultralong HAP nanowires are studied for the first time by focusing on the wet end chemical parameters, the effects of these parameters on the properties such as flocculation, retention, draining, and white water circulation of the fire-resistant paper pulp, and their effects on the properties of the as-prepared fire-resistant paper. The experimental results indicated that the wet end chemical properties of the new kind of fire-resistant paper pulp based on ultralong HAP nanowires were unique and entirely different from those of the traditional paper pulp based on plant fibers. The wet end chemical properties of the fire-resistant paper pulp were significantly influenced by the inorganic adhesive and its content, which affected the runnability of the paper machine and the properties of the as-prepared fire-resistant paper. The flocculation properties of the fire-resistant paper pulp based on ultralong HAP nanowires were affected by the conductivity and Zeta potential. The addition of the inorganic adhesive in the fire-resistant paper pulp based on ultralong HAP nanowires could significantly increase the conductivity of the fire-resistant paper pulp, reduce the particle size of paper pulp floccules, and increase the tensile strength of the fire-resistant paper. In addition, the fire-resistant paper pulp based on ultralong HAP nanowires in the presence of inorganic adhesive exhibited excellent antibacterial performance. This work will contribute to and accelerate the commercialization process and applications of the new type of the fire-resistant paper based on ultralong HAP nanowires.     

水性纸品上光涂料的研究进展

水性纸品上光涂料是用于印刷品的精加工及包装材料的表面整饬的一种涂料,具有成本低、无污染、无毒无害、性能优良,运输方便等优点,是当前印刷上光涂料的主要发展方向。目前,国内的水性纸品上光涂料生产技术多样化,质量参差不齐,且成本高,耐水、耐磨、光泽度性能都达不到高档印刷品的上光要求,70%的高档水性纸品上光涂料需要依靠进口。本文系统地介绍了目前国内外水性纸品上光涂料的研究进展,总结了水性纸品上光涂料的各自特点与应用,并提出一种水性纸品上光涂料制备的新方法。     

Influence of Nanocellulose Structure on Paper Reinforcement

This article describes how crystalline or fibrous nanocellulose influences the mechanical properties of paper substrate. In this context, we used commercially available cellulose nanocrystals, mechanically prepared cellulose nanofibers dispersed in water or ethanol, and carboxy cellulose nanofibers. Selective reinforcement of the paper treated with the nanocellulose samples mentioned above was observed. The change in the fibre structure was assessed using scanning electron microscopy, roentgenography, and spectroscopy techniques. In addition, the effect of nanocellulose coating on physical properties was evaluated, specifically tensile index, elongation coefficient, Elmendorf tear resistance, Bendtsen surface roughness, Bendtsen air permeability, and bending strength. It can be concluded that the observed decrease in the strength properties of the paper after applying some NC compositions is due to the loss of potential disturbances in hydrogen bonds between the nanocellulose dispersed in ethanol and the paper substrate. On the other hand, significantly increased strength was observed in the case of paper reinforced with nanocellulose functionalized with carboxyl groups.     

Effects of Carbon Nanotube Paper Properties on Enzymatic Bioanodes

Carbon papers are frequent current collectors in fuel cells, but recently carbon nanotube papers have been introduced as new types of carbon paper. They have varying thickness, surface area, density, gas permeability, and conductivity. This paper studies the effect of these properties on electrochemical performance. Electropolymerizing methylene green on each carbon nanotube papers was performed to study the papers’ ability to oxidize NADH. Secondly, glucose bioanodes were formed with carbon nanotube papers to study glucose bioelectrocatalysis. The optimal carbon nanotube paper had a high surface area, low gas permeability, and low sheet resistance. Our results showed a greater than three‐fold increase in sensitivity over commercially available Toray carbon paper.     

A Study of the Hydrolysis of Waste Paper Cellulose with a Vertically Hanging Immobilized Cellulase Reactor and the Reuse of the Immobilized Cellulase

A commercialized cellulase from Trichoderma reesei has been successfully immobilized by using calcium alginate gel in our laboratory. The waste paper cellulose was hydrolyzed with a special design of the reactor to form a vertically hanging immobilized cellulase under the optimum conditions of pH 4.0 and 45 °C. Glucose, cellobiose and xylose are the major hydrolysis products. The glucose production from the hydrolysis with the vertically hanging immobilized cellulase was about 1.73‐fold better than the freely suspended immobilized cellulase. The average diameter of the immobilized cellulase pellets was 4.190 ± 0.291 mm. UV light irradiation deactivates the activity of the immobilized cellulase. The advantage of the vertically hanging immobilized cellulase reactor is an easy recycle and reuse of the immobilized cellulase. Washing and soaking the recycled immobilized cellulase with distilled water for one day can restore its activity to a small extent. Overall, the application of the hanging immobilized cellulase reactor for waste paper cellulose hydrolysis is successful.     

超疏水滤纸的制备与应用

对SiO2纳米粒子进行硅烷化改性,再将其修饰到滤纸上,制备出静态水接触角＞150°的超疏水滤纸,对制备条件进行了优化。 用热重分析及扫描电子显微镜对超疏水滤纸表征后发现,二氧化硅纳米粒子在滤纸纤维表面形成一层包裹层,即纳米级粗糙结构,这种结构对滤纸的疏水性具有关键作用。 对滤纸的油水分离性能进行了研究,发现其对非均相体系和高粘度油水混合物具有很好的分离效果。     

Paper spray tandem mass spectrometry: A rapid approach for the assay of parabens in cosmetics and drugs

A fast methodology for the assay of parabens in drug and cosmetic preparations has been presented. The procedure developed is based on paper spray tandem mass spectrometry and isotope dilution approach. For each investigated paraben, the corresponding labeled standard has been used in order to improve the accuracy and reproducibility of the analyses. The MS experiments have been performed under MRM conditions, monitoring the transitions [M‐H]^? → m/z 92 and [M‐H]^? → m/z 98, respectively, for each analyte and the corresponding labeled internal standard. The quantitative assay has been performed using a calibration curve built from 2 to 15 mg/L. The method accuracy, in all case near 100%, was evaluated using fortified samples at two concentration levels, which are representative of the lower and the higher portion of calibration curve. The good values of LOQ, LOD, and reproducibility confirm the consistency of the developed approach.