Analyses of non-aqueous reactive polymer insulation layer in high geothermal tunnel

The scenario of geothermal tunnel is commonly observed around the world,and increases with the new constructions in the long and deep tunnels,for example in China.Tunnel insulation is generally divided into active and passive insulation.In passive insulation,it is an effective way to set low thermal con-ductivity materials as the thermal insulation layer as the choice of insulation material mainly depends on the thermal conductivity.Polymer is a kind of material with good geothermal performance,but there are relatively few studies.In this context,the transient plane source(TPS)method was used to measure the thermal conductivity of the developed polymer.Then,the temperature field of the high geothermal tunnel insulated by the non-aqueous reactive polymer layer was simulated.With the parametric analysis results,the suggestions for the tunnel layers were proposed accordingly.It revealed that the thermal conductivity of polymer first increases and then decreases with temperature.There are two rising sec-tions(?40e10?C and 20e90?C),one flat section(10e20?C)and one descending section(>90?C).It is observed the thermal conductivity of polymer increases with increase of the density of insulation layer and the density,and the thermal conductivity decreases when exposed to high temperatures.The temperature of the surrounding rocks increases with increase of the thermal conductivity and the thickness of polymer.Finally,a more economical thickness(5 cm)was proposed.Based on the parametric study,a thermal insulation layer with thermal conductivity less than 0.045 W/(m K),thickness of 5 cm and a density less than 0.12 g/cm 3 is suggested for practice.

Identification of origin of insulating polymer maneuvered photoredox catalysis

Solid non-conjugated polymers have long been regarded as insulators due to deficiency of delocalizedπelectrons along the molecular chain framework.Up to date,origin of insulating polymer regulated charge transfer has not yet been uncovered.In this work,we unleash the root origin of charge transport capability of insulating polymer in photocatalysis.We ascertain that insulating polymer plays crucial roles in fine tuning of electronic structure of transition metal chalcogenides(TMCs),which mainly include altering surface electron density of TMCs for accelerating charge transport kinetics,triggering the generation of defect over TMCs for prolonging carrier lifetime,and acting as hole-trapping mediator for retarding charge recombination.These synergistic roles contribute to the charge transfer of insulating polymer.Our work opens a new vista of utilizing solid insulating polymers for maneuvering charge transfer toward solar energy conversion.

聚合物基隔热泡沫材料的制备及其研究进展

以聚合物为基体的多孔材料即聚合物泡沫材料具有比强度高、隔热优良、质量轻、隔音性能好、性价比高等优势。简述了聚合物基隔热泡沫材料的制备方法的发展历史。对聚合物泡沫材料的导热机理进行了归纳,汇总了近些年聚合物基隔热泡沫材料的相关研究,概述了聚合物基泡沫材料结构与导热性能之间的关系。分析了目前常用隔热泡沫材料制备方法的优缺点,指出超临界流体发泡技术由于环保、无毒等优点被广泛应用在隔热聚合物泡沫材料的制备中,且可通过调整温度、压力和外场等对泡孔的尺寸、发泡倍率等进行调控。

结合电子束辐照与压电压力波法空间电荷分布实时测量的空间电荷包迁移行为的研究

空间电荷包现象是一种特殊的空间电荷现象,具体表现为空间电荷以包的形态沿着极化电场的方向进行迁移.目前针对空间电荷包现象的研究还存在一些不足,研究的对象通常集中在聚乙烯及其交联产物中的正极性空间电荷包.本文提出了一套用于负极性空间电荷包特性研究的一体化实验系统,可进行电子束辐照与压电压力波法空间电荷分布实时测量相结合的实验研究,并简要介绍了该系统的结构与功能.该系统适用于不同厚度范围的各类绝缘电介质样品在不同电场下的实验研究.本文使用该实验系统初步研究了在不同外加电场(15,20,2.5,30 kV/mm)下聚丙烯与聚甲基丙烯酸甲酯样品内负极性空间电荷包的迁移行为,并从实验结果中提取了负极性载流子;(电子)的迁移特性.聚丙烯与聚甲基丙烯酸甲酯样品中电子的迁移速率均存在随着电场的增加而减小的负微分迁移率现象,聚丙烯中该现象出现的阈值电场约为26.0 kV/mm,聚甲基丙烯酸甲酯中该现象出现的阈值电场约为19.5 kV/mm,消失的截止电场约为27.5 kV/mm.

隧道防水减震隔热一体化关键技术研究

西部地区交通隧道建设面临全球最为复杂的工程地质条件。受高烈度地震带、富水环境与高低温带等不良地质影响,隧道震害、水害与冻热害问题突出,隧道防水减震隔热一体化技术研究需求迫切。为此,针对多致灾因素下的交通隧道安全建养问题开展系统研究。首先,在前期研发的新型韧性非水反应高聚物材料基础上,进行隧道防水阻渗、减震隔震与保温隔热相关技术研究,开展抗渗试验、减震试验和导热系数测定试验及仿真分析。研究表明,0.6 g/cm^(3)的高聚物材料抗渗等级达到10级,具有良好的防水性能;采用外包高聚物隔震层的隧道复合衬砌结构可减少36%地震波作用下的隧道变形;温度较低时,高聚物导热系数随密度增大而呈现增大趋势,密度每增加1 g/cm^(3),导热系数增大0.1709 W/(m·K),温度较高时,高聚物导热系数随密度增大而呈现先增大后减小趋势;进一步提出隧道“围岩-初衬-高聚物-二衬”复合式衬砌支护体系。最后,开展隧道高聚物防水减震隔热层喷涂施工物理模型试验与现场技术示范,给出最佳喷涂工艺参数,实现隧道防水-减震-隔热功能的一体化应用。相关研究成果可为高烈度、富水环境及高低温带交通隧道安全设计与施工提供借鉴。

Fabrication and Thermal Insulating Properties of ITO/PVB Nanocomposites for Energy Saving Glass

Chemical co-precipitation method was used to synthesize tin-doped indium oxide（ITO）nanoparticles,and the subsequent solution co-blend was employed to fabricate ITO/PVB nanocomposites.UV（Ultra-violet）-Vis（Visible）-NIR（Near Infrared） spectra show that the addition of ITO nano particles can significantly enhance the thermal insulating efficiency of ITO/PVB nanocomposites.With increasing ITO content,the thermal insulating efficiency is increased.UV is almost fully absorbed by all ITO/PVB nanocomposites.Vis transmittance-haze spectra reveal that ITO/PVB nanocomposites exhibit higher Vis transmittance over 71.3%and lower haze below 2%when ITO content is in the range of 0.1 wt%-0.7 wt%.The UV-Vis-NIR spectroscopy shows that,under the premise of over 70%transmittance to the visible light,the screening effect of the NIR can be enhanced by 80%with 0.7%ITO/PVB nanocomposite membrane compared with the undoped PVB.The thermal insulating tests indicate that,in comparison with the pure PVB film,nanocomposite films with 0.1 wt%-0.9 wt%ITO can reduce temperature by 3-8 ℃.The results show that this novel nanocomposite can be used for energy-saving glass.

Fabrication and Thermal Insulating Properties of ATO/PVB Nanocomposites for Energy Saving Glass

The pechini method was used to synthesize antimony-doped tin oxide （ATO） nanoparticles, and the subsequent solution co-blend was employed to fabricate ATO/PVB nanocomposites. Uv-Vis-NIR spectra show that the addition ofATO nano particles can significantly enhance the thermal insulating efficiency of ATO/PVB nanocomposites. With the increase of ATO content, the thermal insulating efficiency is increased. Uv is almost fully absorbed by all ATO/PVB nanocomposites. Vis transmittance-haze spectra reveal that ATO/ PVB nanocomposites exhibit higher Vis transmittance of over 72.7% and lower haze of below 2% when ATO content is in the range of 0.1 wt%-0.5 wt%. The thermal insulating tests indicate that in comparison with the pure PVB film, nanocomposite films with 0.1 wt%-0.5 wt% ATO can reduce temperature of 1-3 ℃, suggesting that this novel nanocomposite can be used for energy-saving glass.

High T_(g) Polymer Insulator Yields Organic Photovoltaic Blends with Superior Thermal Stability at 150℃

Record-breaking organic solar cells(OSCs)based on blends of polymer donors and small molecule acceptors often show undesirable degradati on,which severely precludes their practical use.Herei n,we demonstrate a facile and cost-effective approach to con struct thermally stable OSCs at 150℃ by incorporating a small amount of a polymer insulator polyacenaphthylene(PAC)with high glass-transition temperature over 230℃ into polymer:acceptor blends.The model PTB7-Th:EH-IDTBR blend with 10 wt%PAC maintained above 85%of its initial efficiency upon continuous heating at 150℃ for over 800 h,while the efficiency of the blend without PAC sharply dropped by 70%after-300 h.Owing to high miscibility with acceptors,PAC confines the motion of the acceptor molecules and suppresses the acceptor crystallization at elevated temperatures,leading to significantly improved stability.Importantly,the effectiveness of this blending approach was also validated in many other OSC systems,showing great potential for achieving high-performance thermally stable electronics.

Preparation and Recipe Optimization of Water-based Architectural Heat Insulation Coatings

Water-based architectural heat insulation coatings were studied to overcome the drawbacks of conventional inorganic silicate heat insulation coatings. The heat insulation coatings were prepared with the method of mechanical agitation when the mixed organic polymer emulsions were used as binder of the coatings and the mixed heat insulating aggregates were applied as powder, and some assistants were also added. Water temperature difference in the plastic container, which was coated with heat insulation coatings, represented the heat-insulating property of the coatings. The influences of components of mixed polymer emulsion, mass ratio of polymer emulsion to powder, particle size of heat insulating aggregates, added amount of air entraining admixture and the match of thickeners on the properties of the coatings were studied. The experimental results show that the heat insulation coatings with good finishing, heat-insulation property and artificial weathering can be prepared when the binder is composed of 66.92% styrene-acrylic emulsion, 16.59% elastic emulsion and 16.49% silicone-acrylic emulsion, the mass ratio of polymer emulsion to powder is 0.45, the particle size of heat insulating aggregates is in the rang of 200 and 250 mesh size, the added amount of sericite is 15%, and the added amount of air entraining admixture is in the range of 1.0% and 1.5% and the thickeners are the mixtures of ASE-60 and RM-5000.

柔性增强二氧化硅气凝胶的研究进展

传统二氧化硅气凝胶隔热性能优异、制备工艺成熟,但固有的脆性严重限制了其推广使用。阐述了近年来硅气凝胶柔性增强方面的研究进展,通过详细分析现有柔性增强研究中存在的问题,提出组分增强时要通过适当选择硅烷前驱体,并将其与有机聚合物或纤维复合来构建柔性网络骨架,实现化学结构和网络骨架的调控;在工艺优化方面,详细介绍了仿生干燥技术和3D打印技术2种新工艺。最后,根据柔性气凝胶的未来发展方向,对突破常压干燥技术、开展聚合物交联或纳米纤维增强制备结构有序可控的柔性复合气凝胶进行了展望。

无卤阻燃聚合物绝缘材料研究进展

聚合物因其优异的电绝缘性能、力学性能、加工流变性能等被广泛应用于电力设备如电线电缆、绝缘子等的电气绝缘。随着输变电系统电压等级的升高及电线电缆的大负荷传输,因电线电缆绝缘问题引发的火灾日趋严重,由此导致的生命及环境危害引起高度重视,因而对聚合物绝缘材料的阻燃性能提出更高要求。综述了针对电线电缆绝缘的无卤阻燃聚合物绝缘材料研究进展,讨论了材料组成、结构、性能及其阻燃机理,阐明了其性能优势及不足,以期为该类材料的研发及其在高电压等级电气绝缘领域的应用提供依据。

聚合物基导热绝缘复合材料研究与应用进展

导热绝缘材料是保障微电子设备、电力装备工作效率和稳态运行必不可少的部分,但随着设备功率的提高,目前主流的硅基材料难以满足高集成技术、微电子封装、大功率电力装备等关键技术对材料导热、绝缘以及力学性能的要求,亟待开发下一代导热绝缘材料。聚合物基导热绝缘材料因其优异的绝缘、导热和机械延展等优异特性而被广泛关注,该文主要以聚合物基复合材料内部结构对导热、绝缘及力学性能的影响为基础,分析总结填料种类、含量、填料尺寸以及填料的复合网络对聚合物热导率的影响规律,并对复合材料的结构设计方法及在各领域的应用现状进行全面梳理与总结,为高导热绝缘复合材料的设计与性能优化提供指导,推动其规模化应用。

电气绝缘用非线性电导材料研究进展

具有非线性电导特性的聚合物材料被广泛应用于解决电场集中问题,例如用来实现电缆附件绝缘、高压旋转电机定子绝缘及大功率绝缘栅双极晶体管等部件的电应力控制等。该文从几何应力控制及非线性应力控制两方面介绍了电气元器件应用中均化电场的方式,详细地介绍了氧化锌与碳化硅等无机导电颗粒的非线性电导特性及其聚合物基复合材料的非线性电导形成机制。基于渗流理论及界面传导等理论阐述了掺杂填料含量对非线性电导特性的影响规律,以掺杂填料接触电阻大小、接触界面数目、晶界数量等方面为切入点,总结了填料形貌、尺寸对非线性电导复合材料载流子传输的影响机制。介绍了多维度填料共掺及填料表面改性在非线性电导材料领域的应用及性能调控机制,并且概括了非线性电导材料在高压应用中调控电场的研究成果。文中也指出改性复合材料往往具有复杂的结构,在很多情况下有应用限制,且载流子的传输机制尚未统一,仍需进行更深入的研究。

高降噪聚合物基复合材料的制备及声学性能研究进展

从聚合物吸声材料和隔声材料两方面入手,简要介绍了多孔吸声材料、多层吸声材料、复合多孔吸声材料,单层隔声材料以及多层隔声材料的作用机理;基于现有材料性能的局限性,综述聚合物复合降噪材料的制备方法和提高降噪性能的途径;此外,结合文献介绍了层状复合降噪材料、环保型复合降噪材料和声学超材料的制备及声学特性研究进展,为今后降噪聚合物材料的研究提供了方向;最后,简要展望了高降噪复合材料的发展前景。

抗静电泡沫塑料研究进展

泡沫塑料的高绝缘性会造成静电荷的积累,产生高静电电压,从而导致静电危害。本文从抗静电的原理和方法入手,介绍了抗静电泡沫塑料近几年的国内外研究进展,总结了抗静电泡沫塑料目前存在的问题,并展望了其未来的发展方向。

聚氨酯高聚物注浆材料的制备及性能研究

制备了不同密度(0.1,0.3,0.5,0.7g/cm^(3))的双组份聚氨酯高聚物注浆材料,通过FT-IR、SEM、应力-应变、导热系数和冻融循环等测试,研究了不同密度对注浆材料力学性能、保温性能和抗冻性能的影响。结果表明,密度的差异并未对聚氨酯的结构造成影响,没有产生新的特征峰。随着密度的适当增大,注浆材料的胞体尺寸变小,胞体的数量增多,胞体的均匀性和强度得到改善。随着密度的增加,注浆材料到达稳定阶段对应的最大应力、抗压强度和弹性模量均先增大后减小,当密度为0.5 g/cm^(3)时,注浆材料稳定阶段对应的应力最大为11.09 MPa,抗压强度最大为10.02 MPa,弹性模量最大为189.62 MPa。制备的注浆材料导热系数分布区间为0.06~0.08 W/(m·K),具有低导热系数,隔热保温性能较好。在40次冻融循环后,当密度为0.5 g/cm^(3)时,注浆材料的冻融循环强度的损失率最低为16.06%,抗冻性能优异。

Thermal reliability analysis and optimization of polymer insulating through-silicon-vias(TSVs) for 3D integration

Polymer insulating through-silicon-vias(TSVs)is an attractive approach for high-performance 3D integration systems.To further demonstrate the polymer insulating TSVs,this paper investigates the thermal stability by measuring the leakage current under bias-temperature condition,studies the thermal stress characteristics with Finite Element Analysis(FEA),and tries to improve the thermal mechanical reliability of high-density TSVs array by optimizing the geometry parameters of pitch,liner and redistribution layer(RDL).The electrical measurements show the polymer insulating TSVs can maintain good insulation capability(less than 2 10 11A)under challenging bias-temperature conditions of 20 V and 200 C,despite the leakage degradation observation.The FEA results show that the thermal stress is significantly reduced at the sidewall,but highly concentrates at the surface,which is the potential location of mechanical failure.And,the analysis results indicate that the polymer insulating TSVs(diameter of 10 m,depth of 50 m)array with a pitch of 20 m,liner thickness of 1 m and RDL radius of 9m has an optimized thermal-mechanical reliability for application.

A comparative analysis of dielectric properties of oil-paper insulation and polymer materials before and after thermal aging

The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil,restricted the development of transformer with smaller size and larger capacity.In view of this situation and the transformer’s demand for the dielectric physicochemical and mechanical property of insulation material,polycarbonate,polyester film and polyphenylene sulfide with high high-temperature resistance were chosen for the comparison analysis in this paper We did the 300-day thermal aging experiment on four samples in transformer oil under different aging temperatures of90°C,110°C and 130°C,then analyzed the changes of their dielectric properties.The experiment results are as follows;the permittivity and dielectric dissipation factor of the three polymer materials are apparently smaller than those of the paper both before and after 300-day aging;the volume resistivity and partial discharge inception voltage of the three materials are higher than those of the paper both before and after aging;and the breakdown field strength of polycarbonate is higher than that of the paper both before and after aging,while that of polyester film and polyphenylene sulfide are slightly lower than that of the paper.

大型博物馆浮筑楼板减振技术应用

浮筑楼板系统主要包括弹簧减震系统、隔振垫系统等,具有良好的减震、隔声效果,在工程中应用越来越普遍。依据首都博物馆东馆工程,针对邻近地铁区域博物馆文物库房浮筑楼板作法进行研究,形成了一套集高分子垫块减振、高密度隔声棉填充、复合隔声垫隔声工艺的浮筑楼板设计体系,保证了首都博物馆馆库区地面施工质量,达到了减振隔声的效果。