Study on Glass Fiber Dispersion Technology in SiO_2 Aerogel-glass Fiber Composite Insulation Materials

In order to improve the mechanical properties of SiO_2 aerogel-glass fiber composites, effects of different solvents(cyclohexane, n-hexane, ethanol, acetone) and different dispersing modes(planetary ball milling, ultrasonic dispersion and mechanical stirring) and dispersing duration(10-40 min) on the dispersion of chopped alkali-free glass fiber bundles were studied to determine the best dispersion process. On this basis, the materials were batched according to the mass fraction of SiO_2 aerogel powder to chopped alkali free glass fiber bundles of 90:10, and a certain amount of zinc oxide light-screening agent and phenolic resin binder were added. SiO_2 aerogel glass fiber composite specimens were prepared by direct adding chopped alkali free glass fiber bundles and pre-dispersed chopped alkali free glass fiber bundles, respectively. The cold crushing strength and the thermal conductivity at different surface temperatures(300, 400, 500 and 600 ℃, respectively)of the specimens were measured. The results show that:(1) the optimum dispersion process of chopped alkali-free glass fiber bundles is using ethanol as solvent and mechanical stirring for 30 min;(2) pre-dispersion of chopped alkali-free glass fiber bundles has little effect on the thermal conductivity of SiO_2 aerogel-glass fiber composites but can improve the cold crushing strength.

Preparation of Nanoporous Thermal Insulating Materials and Their Application as Ladle Linings

The nanoporous thermal insulating material was prepared by using fumed silica,SiC powder and glass fiber as starting materials,the appropriate thickness of the nanoporous thermal insulating material lined in ladle was discussed by the simulation method,and the effect of its application as ladle lining was investigated.The results show that the thermal conductivity of the nanoporous thermal insulating material prepared in composition of fumed silica： SiC powder： glass fiber =75： 20：5 （in mass） is 0.023 W · m^-1 · K^-1 at 1 000 ℃,the appropriate thickness of the nanoporous thermal insulating material lined in ladle is ≤ 5 mm and the average temperature of the ladle outside surface when lined with the nanoporous thermal insulating material is 95 ℃ lower than that with the ordinary thermal insulating material.

Preparation and Properties of TiO2-Coated Hollow Glass Microspheres as Thermal Insulation Materials for Energy-Saving Buildings

A hollow glass microsphere(HGM)/TiO2 composite hollow sphere was successfully prepared via a simple precipitation method.The TiO2 coating layers grew on the surface of the HGMs that range from 20 to 50μm in diameter as nanoparticles with the formation of the SiO Ti bonds.The growth mechanism accounting for the formation of the TiO2 nanolayers was proposed.The morphology,composition,thermal insulation properties,and visible-near infrared(VIS-NIR)refl ectance of the HGMs/TiO2 composite hollow spheres were characterized.The VIS-NIR reflectance of the HGMs/TiO2 composite hollow spheres increased by more than 30%compared to raw HGMs.The thermal conductivity of the particles is 0.058 W/(m K).The result indicates that the VIS-NIR reflectance of the composite hollow spheres is strongly influenced by the coating of TiO2.The composite hollow spheres were used as the main functional filler to prepare the organic-inorganic composite coatings.The glass substrates coated by the organic-inorganic coatings had lower thermal conductivity and higher near infrared reflectivity.Therefore,the HGMs/TiO2 composite hollow spheres can reflect most of the solar energy and effectively keep out the heat as a thermal insulation coating for energy-saving constructions.

Research on thermal insulation materials properties under HTHP conditions for deep oil and gas reservoir rock ITP-Coring

Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.

Fabrication and Characterization of Bamboo—Epoxy Reinforced Composite for Thermal Insulation

As global warming intensifies, researchers worldwide strive to develop effective ways to reduce heat transfer. Among the natural fiber composites studied extensively in recent decades, bamboo has emerged as a prime candidate for reinforcement. This woody plant offers inherent strengths, biodegradability, and abundant availability. Due to its high cellulose content, its low thermal conductivity establishes bamboo as a thermally resistant material. Its low thermal conductivity, enhanced by a NaOH solution treatment, makes it an excellent thermally resistant material. Researchers incorporated Hollow Glass Microspheres (HGM) and Kaolin fillers into the epoxy matrix to improve the insulating properties of bamboo composites. These fillers substantially enhance thermal resistance, limiting heat transfer. Various compositions, like (30% HGM + 25% Bamboo + 65% Epoxy) and (30% Kaolin + 25% Bamboo + 45% Epoxy), were compared to identify the most efficient thermal insulator. Using Vacuum Assisted Resin Transfer Molding (VARTM) ensures uniform distribution of fillers and resin, creating a structurally sound thermal barrier. These reinforced composites, evaluated using the TOPSIS method, demonstrated their potential as high-performance materials combating heat transfer, offering a promising solution in the battle against climate change.

Microwave absorption and thermal properties of coral-like SiC aerogel composites prepared by water glass as a silicon source

As a heat-resistant wave-absorbing material,silicon carbide(SiC)aerogel has become a research hotspot at present.However,the most common silicon sources are organosilanes,which are costly and toxic.In this work,SiC aerogels were successfully prepared by using water glass as the silicon source.Specifically,the microstructure and chemical composition of SiC aerogels were controlled by adjusting the Si to C molar ratio during the sol–gel process,and the effect on SiC aerogel microwave absorption properties was investigated.The SiC aerogels prepared with Si:C molar ratio of 1:1 have an effective electromagnetic wave absorption capacity,with a minimum reflection loss value of-46.30 dB at 12.88 GHz and an effective frequency bandwidth of 4.02 GHz.They also have good physical properties,such as the density of0.0444 g/cm^(3),the thermal conductivity of 0.0621 W/(m·K),and the specific surface area of 1099 m^(2)/g.These lightweight composites with microwave-absorbing properties and low thermal conductivity can be used as thermal protection materials for space shuttles and reusable carriers.

Anisotropic Structure of Glass Wool Determined by Air Permeability and Thermal Conductivity Measurements

We want to conclude on the interest of the “crimping” process used to produce the glass wool and to make a comparison for anisotropic factor obtained from structural property (air permeability) as well as thermal property (thermal conductivity and diffusivity). The main structural (densities, porosity, specific surface, air permeability) and the thermal (conductivity, diffusivity, heat capacity) characteristics of this glass wool are presented. Thermal results are determined by using several methods (Hot disc (HD), Heat Flow Meter (HFM) and Guarded Hot Plate).

聚丙烯/玻璃纤维复合泡沫的制备及隔声隔热性能

以二缩三丙二醇二丙烯酸酯(TPGDA)和苯乙烯(St)为单体,过氧化二异丙苯(DCP)为引发剂,玻璃纤维(GF)为填料,通过熔融共混法和模压发泡法制备了聚丙烯(PP)/GF复合泡沫,利用PP分子上熔融接枝形成的TPGDA-St共聚物长链支化结构作为相容剂,促进GF在PP基体中的分散,通过GF与TPGDA-St共聚物长链支化结构的协同作用,有效改善PP熔体和复合泡沫的性能。研究了支化结构相容剂和填料用量对PP熔体强度、热稳定性、结晶性能以及复合泡沫微观形貌、隔热性能、声学性能、力学性能的影响。结果表明,TPGDA-St共聚物长链支化结构相容剂能够有效促进GF在PP基体中的分散,强化界面相互作用,形成较为完善的填料网络,显著提升了PP的熔体强度、发泡性能和结晶性能。当GF用量为10份时,PP/GF复合泡沫的泡孔均匀、形状规则、压缩性能良好,具备优异的隔声性能和隔热性能,平均声音传输损耗达到59.7 dB,相较于纯PP泡沫提高了84.8%,导热系数低至0.055 W/(m·K),相较于纯PP泡沫降低了65.6%。

35kV输电线路玻璃绝缘子串中残锤的危害分析

针对35 kV输电线路玻璃绝缘子零值自爆后的残锤,分析残锤的外绝缘、内绝缘特性,并结合两个实例分析在大风大雨作用下35 kV输电线路玻璃绝缘子串中残锤的危害,还针对残锤的危害提出了反措。结果表明:雨水可通过残锤的外绝缘渗浸内绝缘;运行中若未能及时发现和更换残锤,大风大雨将有可能引发存在残锤的35 kV输电线路玻璃绝缘子串发生单相接地闪络故障。其中,在残锤的内绝缘没有被雨水渗浸前,其内绝缘水平高于外绝缘水平,闪络电弧从残锤的外绝缘直接拉弧导通,将有可能导致单相接地闪络故障延时跳闸的35 kV输电线路发生烧断导线故障;在残锤的内绝缘被雨水渗浸后,其内绝缘水平低于外绝缘水平,闪络电弧从被雨水渗浸的残锤内绝缘导通,将有可能发生35 kV输电线路掉串故障。

(Ag,Cu)/TiO_(2)汽车玻璃隔热膜的制备与表征

利用磁控溅射技术制备由金属(Ag,Cu)膜、介质层TiO_(2)膜组成的双层汽车玻璃隔热膜样品。利用单因素分析法考察了溅射时间、溅射功率和Ar溅射流量三个因素对(Ag,Cu)/TiO_(2)汽车玻璃隔热膜透光隔热性能的影响。实验结果表明,在在本底真空度3×10^(-3) Pa,溅射气压2.1 Pa条件下,靶基距均为70 mm时,金属(Ag,Cu)膜溅射时间18 s,溅射功率80 W,Ar溅射流量20 sccm;介质层TiO_(2)膜溅射时间50 min,溅射功率115 W,溅射流量25 sccm时,(Ag,Cu)/TiO_(2)汽车玻璃隔热膜的透光隔热性能最佳。

薄型中空玻璃与发展路径和方向

减薄中空玻璃材料及中空玻璃整体厚度均属于薄型中空玻璃的范畴。薄型中空玻璃可实现节材、节能和节碳多重效益。本文简析了薄型中空玻璃主要种类、制作、成本状况和发展趋势。中置薄玻璃中空玻璃具有产业化基础和成本优势,转型发展具有广阔前景。中置膜材料中空玻璃和真空玻璃复合中空玻璃薄型化程度高,具有良好的适应性发展趋势。气凝胶中空玻璃作为未来发展方向,在采光为目的的围护结构中有应用优势。

影像变形的中空玻璃厚度测量与分析

选取某玻璃幕墙项目同一区域内已有影像变形的不同分格尺寸的中空玻璃,测量了中空玻璃空气层厚度和中空玻璃外片平面外凹陷,并对中空玻璃外片凹陷变形进行等效荷载作用校核分析,为影像变形的中空玻璃整改和安全使用提供了数据支持。

一起35 kV线路两基相邻直线杆玻璃绝缘子串的多点故障分析

针对一起35 kV线路两基相邻直线杆玻璃绝缘子串的残锤、雨闪、电弧风偏及断线等的多点故障,笔者分析了故障原因,并提出改进措施。结果表明:该线路19号杆仅有2片绝缘子、1个残锤的A相2片串发生持续间歇雨闪,扣除残锤后绝缘子的每串最少片数少于规范要求值、单相雨闪故障延时跳闸等是引发该起故障的主要原因;35 kV线路采用4片玻璃绝缘子串或改用复合绝缘子,加强绝缘子串的可恢复绝缘、抗污及灭弧性能,可防止发生此类故障。

掺银硫系玻璃光电探测器响应波长特性研究

由于硫系玻璃具有良好的光学性质,在非线性光学等方面研究广泛,但基于硫系玻璃光电探测器的相关研究却很少。本文利用真空共热蒸发技术制备了不同掺银比例的硫系玻璃薄膜作为半导体膜层结构,并设计构建了金属-绝缘体-半导体结构的自供电光电探测器,探究了该光电探测器的响应光谱范围。结果表明,该探测器对可见光到近红外区域的光均有响应。针对掺银硫系玻璃光电探测器在635 nm波长激光下,研究了探测器响应电压与激发功率之间的关系。当激光功率小于10 mW时,探测器响应电压与激发功率线性相关;当激光功率大于10 mW时,探测器响应电压逐渐饱和。探测器的上升和衰减时间分别为3.932 s和1.522 s。本研究为硫系玻璃材料在自供电光电探测器领域的应用提供了证明。

纳米填料改性环氧树脂建筑保温材料的制备及性能研究

环氧树脂基混凝土作为一种绿色环保的建筑材料,在道路修补和保温建筑中应用广泛。以环氧树脂E44为原料,二甲苯为稀释剂,纳米玻璃纤维为填料,制备了复合环氧树脂基混凝土,研究了不同纳米玻璃纤维长度对混凝土微观形貌、力学性能和保温性能的影响。结果表明,纳米玻璃纤维的掺杂发挥了“晶种”作用,促进了水化反应的进行,提高了环氧树脂基混凝土的密实度。纳米玻璃纤维长度的适当增加提高了混凝土与纤维的结合强度,当纳米玻璃纤维长度为8 mm时,混凝土的形貌最佳。随着纳米玻璃纤维长度的增加,混凝土的抗压强度和抗折强度先增大后降低。养护28 d,当纳米玻璃纤维长度为8 mm时,混凝土的抗压强度和抗折强度均达到最大值,分别为21.93和4.59 MPa。纳米玻璃纤维的掺杂改善了混凝土的孔结构,降低了导热系数,提高了保温性能,当纳米玻璃纤维长度为8 mm时,混凝土导热系数最低为0.147 W/(m·K),保温性能最佳。

有机硅/改性空心玻璃微珠复合材料的制备与性能研究

以缩合型有机硅为有机树脂基体,以改性空心玻璃微珠为无机填料,基于物理复合法制备出不同空心玻璃微珠含量的有机硅/改性空心玻璃微珠复合隔热材料。系统性研究其隔热机理、隔热性能、力学性能和热稳定性能,实现对复合隔热材料孔隙率和隔热性能的精准调控。研究结果表明,所制得的复合隔热材料的压缩强度最大值达到13.28 MPa,是纯有机硅材料的1.49倍,热导率最低为0.113 W/(m·K),比纯有机硅材料减小了37.91%。

空心玻璃微珠在涂料中的应用与研究进展

简述了空心玻璃微珠的表面改性方法以及在涂料中的应用情况,分类总结了其在隔热涂料、防火涂料、吸波涂料和防腐涂料中的最新研究进展,并对未来空心玻璃微珠在涂料中的应用方向拓展进行了展望。

低吸水率水性隔热保温涂料的制备及性能

[目的]随着水性隔热保温涂料在工业涂装领域的广泛应用,其吸水率较高引发的涂层隔热性能下降问题亟需解决。[方法]以苯丙乳液作为主要成膜物,以偶联剂表面改性的中空玻璃微珠作为隔热填料,以涂层的导热系数和吸水率作为主要性能指标,制备了一种低吸水率的水性隔热保温涂料。通过傅里叶变换红外光谱仪(FT-IR)对不同偶联剂处理的中空玻璃微珠进行了表征,通过扫描电子显微镜(SEM)考察了涂层的微观结构和形貌,测试了浸水前后涂层的导热系数、力学性能和粘结强度。[结果]铝酸酯偶联剂的改性效果比硅烷偶联剂好。当铝酸酯偶联剂改性中空玻璃微珠添加量为25%(质量分数)时,涂层的综合性能最优,24 h吸水率为9.32%,浸水168 h后的导热系数为0.1228 W/(m·K),拉伸强度为2.45 MPa,断裂伸长率为28.37%,拉拔法粘结强度为2.32 MPa。[结论]采用合适的偶联剂对中空玻璃微珠进行表面改性可有效改善隔热保温涂料体系中有机-无机界面的相容性,从而降低其吸水率,增强其力学性能。

阻燃隔热防护面料的泡沫整理制备

开发成本低廉的阻燃隔热面料,替代价格昂贵的高性能纤维面料,对于家庭用消防装具的普及和降低消防服装成本有着积极意义。文中在对无机纳米颗粒材料进行表面结构调控和对玻璃纤维进行表面处理的基础上,由泡沫整理实现玻璃纤维织物上黏弹性材料的薄层涂敷,通过对氢氧化铝和玻纤织物的表面处理,在玻纤织物表面应用足量隔热材料时,保证氢氧化铝与有机聚合物材料在玻纤织物表面的耐摩擦牢度和面料的阻燃性能及热防护性能达到要求。结果表明,制备得到的阻燃隔热防护面料,燃烧后碳长2.0mm,阴燃及续燃时间为0,且没有溶滴产生;面料热防护性能为35.80J/cm^(2)·s,达到芳纶的热防护水平;面料功能层的干摩为4级,湿摩为3级。

烧成温度对钙长石隔热耐火材料显微结构与性能的影响

本工作以矾土水泥与黏土为原料,采用发泡法制备了钙长石隔热耐火材料,通过XRD、SEM和导热仪等分析了烧成温度(1110~1310℃)对钙长石隔热耐火材料显微结构与性能的影响,并研究了该种钙长石隔热耐火材料的合成机理。结果表明:当烧成温度为1110~1160℃时,体系内开始生成钙长石,但原料微颗粒间的反应并不完全,生成的液相含量较少,强度较低;当烧成温度为1210~1260℃时,液相含量增多,钙长石的生成速度加快,强度增大,试样具有较低导热系数;当烧成温度为1310℃时,液相含量迅速增多,线收缩率迅速增大,试样具有较大强度,但体积密度大幅增长,气孔率降低。在1260℃时,制得了体积密度为0.53 g/cm^(3)、气孔率为82.6%、抗折强度为1.15 MPa、耐压强度为1.99 MPa、800℃导热系数为0.101 W/(m·K)的钙长石隔热耐火材料。