石墨烯改性导电液体聚硫醚密封剂的制备及其性能研究

以镀镍石墨和石墨烯为导电填料,液体聚硫醚橡胶为基体,制备了导电室温硫化聚硫醚密封材料。研究了镀镍石墨和石墨烯用量对聚硫醚密封剂导电性能、力学性能、耐热性能的影响。结果表明,石墨烯/镀镍石墨复合导电填料体系具有良好的导电性能;在体积电阻率相同的条件下,与镀镍石墨相比,复合导电填料可实现密封剂密度降低约20%。此外,石墨烯具有优异的补强效果,添加石墨烯的密封剂之耐燃油和热空气老化后力学性能保持率显著高于无石墨烯密封剂材料,并且具有更好的耐盐雾和电磁屏蔽性能。     

导电有机硅密封剂的研究

以镀银镍粉为导电填料、端羟基聚二甲基硅氧烷为基胶、经硅烷表面处理的白炭黑为补强填料,有机锡为催化剂,制成了高导电室温硫化双组分有机硅密封剂;研究了导电机理、镀银镍粉的加入量对有机硅密封剂的导电性能和电磁屏蔽性能的影响。结果表明,当镀银镍粉的体积分数超过25%时,有机硅密封剂的电性能明显提高;当镀银镍粉的体积分数达到35%以上时,有机硅密封剂的体积电阻率下降近10个数量级;当镀银镍粉的体积分数为50.5%时,有机硅密封剂在高频率范围具有良好的电磁屏蔽性能。     

石墨镀镍FIP加成型有机硅密封剂的制备和性能研究

以甲基乙烯基硅橡胶为基体,石墨镀镍粉体为导电填料,制备了石墨镀镍FIP加成型有机硅密封剂.考察了石墨镀镍粉体填充量对密封剂力学性能、导电性能的影响,对比了热处理前后密封剂的力学性能随石墨镀镍粉体填充量的变化;同时考察了偶联剂处理石墨镀镍粉体后对密封剂力学性能、导电性能的影响.研究结果表明:经过热处理后的密封剂硬度明显增...     

导电聚硫密封剂研究

随着电子行业的飞速发展,电子设备对电磁环境的要求也更加苛刻,电子设备箱的密封需要使用具备导电功能的密封剂。本文研究了导电炭黑对聚硫密封剂导电性能和力学性能的影响,确定了导电炭黑在聚硫密封剂中的最佳用量,还研究了热空气老化对导电聚硫密封剂性能的影响。结果表明,研究的导电聚硫密封剂可以在高温环境中使用。     

聚硫代醚密封剂压缩性能的研究

通过对密封剂压缩永久变形、压缩模量的测试,考查了不同填料和增粘剂对聚硫代醚密封剂压缩性能的影响。结果表明,以高岭土为填料的聚硫代醚密封剂的压缩性能优于以炭黑和活性碳酸钙为填料的聚硫代醚密封剂,而增粘剂的加入会降低聚硫代醚密封剂的压缩性能。     

表面处理CaCO3对单组分聚氨酯密封剂性能的影响

对轻质CaCO3、重质CaCO3和滑石粉3种填料进行了表面处理,考察了它们对聚氨酯密封剂性能的影响。结果表明：使用表面处理轻质CaCO3作填料的聚氨酯密封剂与使用未处理轻质CaCO3作填料制备的聚氨酯密封剂相比,其邵氏硬度降低,伸长率提高。此外,使用表面处理轻质CaCO3作填料时在增加填料用量的同时,能确保密封剂的物理机械性能。     

高导电硅橡胶与航空密封剂的适配性研究

研究了高导电硅橡胶与聚硫和有机硅航空密封剂的适配性。结果表明，聚硫密封剂HM120对高导电硅橡胶的导电性能不利，会造成硅橡胶表面电阻值增大；HM120的基体中含有双硫键，能够与高导电硅橡胶中添加的银粉发生反应，从而降低胶料的导电性能；而有机硅密封剂HM304对导电性能的影响远小于HM120,在高导电硅橡胶与其它材料之间配合时具有更好的密封匹配性。     

一种新型导电聚硫密封剂的研制

以液体聚硫橡胶为主要原料,通过添加镀镍石墨、导电炭黑等制备了一种新型导电聚硫密封剂。结果表明,此种导电聚硫密封剂体积电阻低于10Ω·cm,且经过热空气老化后导电性能保持稳定。     

填料对聚硫密封剂耐水性能的影响

选择8种常规无机填料,考查了填料对聚硫密封剂力学性能和粘接性能的影响。耐水试验后发现填充煅烧高岭土、气相SiO₂、水洗高岭土的密封剂耐水性能最优,其次是轻质CaCO₃、重质CaCO₃、沉淀SiO₂,填充TiO₂和滑石粉的密封剂性能变化较大。二氧化硅填料单独使用对粘接性能影响大,出现脱粘现象,煅烧高岭土为填料时剥离强度变化最小。     

提高聚硫密封剂粘接性能的研究

论述了填料、偶联剂以及不同硫化体系对聚硫密封剂粘接性能的影响,分析了这些因素影响聚硫密封剂粘接性能的原理以及不同被粘体的表面状态和粘接效果的关系.为提高聚硫密封剂的粘接性能提供了技术依据.     

聚合物基导热复合材料的性能及导热机理

采用不同品种、粒径的导热填料和基体树脂,以熔融共混方法制备聚合物/填料体系导热功能复合材料。研究了复合材料热导率λ和体积电阻率ρ_v随不同填料、粒径等因素的变化规律及其内在原因。不同填充体系的热导率均随填料粒径的减小而降低,而电导率则相反;复合体系热导率随填料含量的增加始终呈逐步上升趋势,未表现出电导率那样的急剧变化。研究表明：复合体系热导率和电导率变化的差异主要是由于二者具有不同的传导机理;复合材料热导率的变化规律可以用热弹性复合增强机制进行合理解释。     

特种车辆用聚氨酯导热绝缘密封胶的研制

以聚醚多元醇和甲苯二异氰酸酯为主要原料、硅烷偶联剂改性氮化铝（AlN）为填料制备了适用于特种车辆中央处理器的电源密封的聚氨酯导热绝缘密封胶,讨论了AlN的平均粒径和用量对该密封胶导热系数、绝缘性能以及力学性能的影响。结果表明,纳米级改性AlN在明显改善密封胶导热性的同时,可以保持材料优异的力学性能;当改性AlN质量分数达到48％时,聚氨酯导热绝缘密封胶的导热系数达到0．453W／（m·K）,表面电阻为1．5×10^9Ω,体积电阻为2．6×10mn,拉伸强度达到0．9MPa,满足特种车辆中央处理器的电源密封要求。     

Electrical conductivity and EMI shielding effectiveness of polyurethane foam–conductive filler composites

The morphological, electrical, and thermal properties of polyurethane foam (PUF)/single conductive filler composites and PUF/hybrid conductive filler composites were investigated. For the PUF/single conductive filler composites, the PUF/nickel‐coated carbon fiber (NCCF) composite showed higher electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) than did the PUF/multiwall carbon nanotube (MWCNT) and PUF/graphite composites; therefore, NCCF is the most effective filler among those tested in this study. For the PUF/hybrid conductive fillers PUF/NCCF (3.0 php)/MWCNT (3.0 php) composites, the values of electrical conductivity and EMI SE were determined to be 0.171 S/cm and 24.7 dB (decibel), respectively, which were the highest among the fillers investigated in this study. NCCF and MWCNT were the most effective primary and secondary fillers, and they had a synergistic effect on the electrical conductivity and EMI SE of the PUF/NCCF/MWCNT composites. From the results of thermal conductivity and cell size of the PUF/conductive filler composites, it is suggested that a reduction in cell size lowers the thermal conductivity of the PUF/conductive filler composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44373.     

DBSA掺杂聚苯胺在导电塑料中的应用

以十二烷基苯磺酸(DBSA)作为掺杂酸合成掺杂态聚苯胺,并以掺杂态聚苯胺和特导炭黑做为导电填料,线性低密度聚乙烯(LLDPE)为基体,乙烯-乙酸乙烯酯(EVA)作为增塑剂,掺杂态聚苯胺和特导炭黑作为导电填料,制备导电塑料。使用四探针法测定了掺杂态聚苯胺和导电塑料的电导率,使用扫描电子显微镜、X射线衍射、红外光谱法、热重法对掺杂态聚苯胺进行分析和表征,并且测试了导电塑料的力学性能和流动性能。研究表明:掺杂态聚苯胺具有良好的导电性能,可以作为导电塑料的导电填料使用;并且使用掺杂态聚苯胺和特导炭黑作为导电填料制备的导电塑料比单独使用掺杂态聚苯胺具有更好的导电性能,力学性能。     

Microcellular Conductive Carbon Black or Graphene/PVDF Composite Foam with 3D Conductive Channel: A Promising Lightweight,Heat-Insulating,and EMI-Shielding Material

In this study, a lightweight microcellular carbon-based filler/poly(vinylidene fluoride) (PVDF) composite foam is fabricated with a 3D conductive network that is thermally insulating, electrically conductive, and fabricated on a large scale. This composite can be used for high-efficiency thermal insulation and electromagnetic interference (EMI) shielding applications. The prepared composite demonstrates low density, high electrical conductivity, and excellent thermal insulation properties. The structure and density of the conductive network and the carbon-based filler content has a significant influence on the electrical conductivity of the prepared composite foam. Although the composite comprises microcellular PVDF beads of the same density, the conductivity of the composite-comprising strip beads is greater than that comprising spherical beads. In the same conductive network structure, as the size of the microcellular PVDF beads decrease, the conductive network becomes denser, which results in a higher conductivity. Furthermore, with an increase in the conductive filler content, the conductivity improves significantly. Excellent EMI shielding materials with optimal filler content and particle shapes, exhibiting EMI shielding effectiveness of up to 40–50 dB, are developed. The prepared composite foam possesses excellent application potential in the fields of ultra-light thermal insulation, conductivity, and EMI shielding.     

Factorial design approach applied to electrically and thermally conductive nylon 6,6

Increasing the thermal and electrical conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. An electrically conductive resin can be used in static dissipative and Electromagnetic Interference/Radio Frequency Interference shielding applications. This research focused on performing compounding runs followed by injection molding and testing (tensile properties, volumetric electrical resistivity, and through‐plane thermal conductivity) of carbon filled nylon 6,6. The four carbon fillers investigated included a PAN‐based carbon fiber (milled, 200μ long), an electrically conductive carbon black, vapor grown graphitic nanotubes, and Thermocarb (high quality synthetic milled graphite). Formulations were produced and tested that contained varying amounts of a single carbon filler. Combinations of fillers were also investigated via conducting half of a 2⁴ factorial design. It was determined that Thermocarb has the largest effect on the thermal conductivity. Increasing Thermocarb increases thermal conductivity. For conductive resins containing only a single filler type, nanotubes caused the electrical resistivity (ER) to decrease the most. For the half fraction factorial design formulations that contain at least one filler type at the higher level, the ER of the conductive resin ranged from 0.1 to 0.3 ohm‐cm.     

Thermal and electrical conductivity of carbon–filled liquid crystal polymer composites

The thermal and electrical conductivity of resins can be increased by adding conductive carbon fillers. One emerging market for thermally and electrically conductive resins is for bipolar plates for use in fuel cells. In this study, varying amounts of five different types of carbon, one carbon black, two synthetic graphites, one natural flake graphite, and one calcined needle coke, were added to Vectra A950RX Liquid Crystal Polymer. The resulting composites containing only one type of filler were then tested for thermal and electrical conductivity. The objective of this work was to determine which carbon filler produced a composite with the highest thermal and electrical conductivity. The results showed that composites containing Thermocarb TC‐300 synthetic graphite particles had the highest thermal and electrical conductivity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99; 1552–1558, 2006     

高导热阻燃有机硅灌封胶的制备

以乙烯基硅油、含氢硅油为基础胶料,十六烷基三甲氧基硅烷改性氧化铝为导热填料,二乙基次膦酸铝(ADP)为阻燃剂,制得导热阻燃绝缘有机硅电子灌封胶。研究了改性氧化铝用量对灌封胶黏度、导热性、阻燃性的影响,观察了燃烧残余物的形貌。结果表明,这种改性氧化铝有低吸油值,填充量对灌封胶黏度影响小,所制备的灌封胶具有良好导热性能;而ADP不仅展现出对灌封胶良好的阻燃性,而且还能与改性氧化铝产生协效阻燃性和抑烟作用,同时灌封胶也具有良好的流动性、力学性能和电绝缘性能。当ADP用量50份、改性氧化铝用量600份时,灌封胶的黏度为8 500 mPa·s,硫化后胶条的热导率达2.12 W/m·K,垂直燃烧达到FV-0级,拉伸强度1.72 MPa,拉断伸长率62%,体积电阻率3.9×1012Ω·cm。     

Electrical,rheological and electromagnetic interference shielding properties of thermoplastic polyurethane/carbon nanotube composites

Electrically conducting rubbery composites based on thermoplastic polyurethane (TPU) and carbon nanotubes (CNTs) were prepared through melt blending using a torque rheometer equipped with a mixing chamber. The electrical conductivity, morphology, rheological properties and electromagnetic interference shielding effectiveness (EMI SE) of the TPU/CNT composites were evaluated and also compared with those of carbon black (CB)‐filled TPU composites prepared under the same processing conditions. For both polymer systems, the insulator–conductor transition was very sharp and the electrical percolation threshold at room temperature was at CNT and CB contents of about 1.0 and 1.7 wt%, respectively. The EMI SE over the X‐band frequency range (8–12 GHz) for TPU/CNT and TPU/CB composites was investigated as a function of filler content. EMI SE and electrical conductivity increased with increasing amount of conductive filler, due to the formation of conductive pathways in the TPU matrix. TPU/CNT composites displayed higher electrical conductivity and EMI SE than TPU/CB composites with similar conductive filler content. EMI SE values found for TPU/CNT and TPU/CB composites containing 10 and 15 wt% conductive fillers, respectively, were in the range ?22 to ?20 dB, indicating that these composites are promising candidates for shielding applications. © 2013 Society of Chemical Industry