导电硅橡胶研究概况

简要介绍导电硅橡胶的导电机理、分类、电学特性以及提高硅橡胶导电性能的途径.导电硅橡胶分为金属粉末填充型和非金属粉末填充型,常用的导电填料有银粉、镰粉、镀银镍粉、石墨、炭黑、碳纳米管和导电纤维等.提高硅橡胶导电性能的途径主要有开发新型导电填料、对导电填料进行表面改性和优化加工工艺.     

填充型导电硅橡胶的制备与性能研究

用导电炭黑EC-600JD和BP2000与石墨烯纳米片填充硅橡胶制备导电硅橡胶,并测试其电性能和力学性能。结果表明:填充导电炭黑BP2000的硅橡胶的电性能优于填充导电炭黑EC-600JD的硅橡胶;在硅橡胶中填充25份导电炭黑BP2000和一定量石墨烯纳米片,随着石墨烯纳米片用量的增大,导电硅橡胶的电性能逐渐提高,当石墨烯纳米片用量为1份时,导电硅橡胶的力学性能最优,电性能较好,达到电热平衡时间最短,压阻特性最不明显。     

抗静电环氧树脂胶粘剂的制备与性能研究

以导电碳黑和银粉为导电填料制备了抗静电环氧树脂(EP)胶粘剂,考察了导电填料的种类和用量对胶粘剂导电性能和力学性能的影响。研究结果表明,导电填料的种类对胶粘剂导电性能和力学性能的影响显著不同;以导电碳黑作为导电填料时,当w(导电碳黑)=5.0%时EP胶粘剂开始具备抗静电能力,当w(导电碳黑)≈7.1%时胶粘剂的体积电阻率发生突跃式下降;而以银粉作为导电填料时,当w(银粉)=0～38%时EP胶粘剂不具备抗静电能力。EP胶粘剂的拉伸强度和剪切强度随着导电碳黑用量的增加呈线性下降的趋势,而随着银粉用量的增加则呈线性上升的趋势。     

炭黑填充复合型导电聚合物的压阻特性

总结了炭黑填充复合型导电聚合物的压阻特性与炭黑导电网络、压力和时间等条件的关系,阐述了加工工艺参数、导电填料、基体性质等对导电聚合物压阻特性的影响,并介绍了通过加入SiO2纳米材料或适当交联基体等改善压阻特性重复性和稳定性的方法.     

炭黑用量对硅橡胶基力敏复合材料性能的影响

以炭黑为导电功能填料制备炭黑/甲基乙烯基硅橡胶(MVQ)力敏复合材料,研究炭黑用量对复合材料硫化特性、拉伸性能、压缩应力松弛性能、电性能和压阻性能的影响.结果表明:炭黑用量为11～16份时,炭黑/MVQ复合材料电性能达到逾渗阈值.随着炭黑用量的增大,炭黑/MVQ复合材料拉伸强度先增大后减小,最后趋于稳定,而压缩松弛率呈减小趋势.炭黑用量为11份时炭黑/MVQ复合材料的压阻重复性较好.适宜的炭黑用量为10～12份.     

导电炭黑/氯化丁基橡胶力学和电性能的研究

通过共混法制备了导电炭黑/氯化丁基橡胶复合材料,研究了复合材料的拉伸性能与导电、介电性能。研究发现,随着导电炭黑和硫化剂含量的增加,拉伸强度先出现一个极大值随后下降,在炭黑用量为5%,硫化剂用量为3%时,拉伸强度最大,为9.1 MPa;而断裂伸长率一直下降。当导电炭黑超过5%以后,电导率迅速增加,出现渗流现象。介电常数实部ε′和介电损耗因子tanδ随导电炭黑用量的增加而增大,但当导电炭黑用量较高(20%)时,在高频时,ε′和tanδ都下降。     

炭黑填充导电硅橡胶导电特性研究概况

简介了导电高分子材料的研究现状;概述了金属系和炭系导电填料的研究进展及导电硅橡胶的导电机理;论述了炭黑填充量、压力和温度对硅橡胶导电性能的影响。     

炭黑／碳化硅复合导电涂料的制备及导电性能研究

制备了一种以炭黑、碳化硅为混合填料的复合导电涂层。研究了炭黑／碳化硅混合填料复合涂层的导电性能,重点研究了混合填料和炭黑种类对涂料导电性能的影响。试验结果表明,混合填料能够明显改善涂层的导电性能,混合填料的炭黑含量在5％时出现渗透阈值,当炭黑含量为25％时电阻率降至10．59Ω·cm。     

硅橡胶/炭黑复合材料在外场作用下的导电响应行为

通过机械共混法制备了甲基乙烯基硅橡胶(MVQ)/炭黑(CB)复合材料,研究了复合材料的压阻特性、温阻特性、在压缩循环下的压阻稳定性和重复性能以及电阻弛豫特性,并提出了新的压阻数学模型。结果表明,在渗滤阈值附近,MVQ/CB复合材料有最显著的压阻效应;随着CB含量的增加,压阻效应出现一个临界压力;在40℃时复合材料由正温阻特性转变为负温阻特性;通过预压缩和增加压缩循环次数,可以提高压敏导电橡胶的压阻重复性和稳定性。应用隧道电流理论构建的压阻效应数学模型能同时很好地模拟MVQ/CB复合材料的正压阻系数效应和负压阻系数效应。     

炭黑／新酚树脂导电复合材料的电学性能研究

为制得新型导电复合材料,首先将新酚树脂羟甲基化,使其耐热性能提高。预处理后的新酚树脂在近 400℃时才开始分解。再以预处理后的新酚树脂为基体、乙炔炭黑为导电填料、玻璃纤维织物为增强材料制备了导电复合材料;确定了材料的导电性与导电填料含量的关系;当炭黑含量为3％时,材料在安全电压下发热温度达到 250℃;研究了导电复合材料的伏安特性,发现其具有非线性欧姆关系;同时也发现制备的导电复合材料具有微弱的正温度系数效应。     

石墨及其表面改性对硅橡胶导热性能的影响

用双辊混炼机将导热填料分散到聚甲基乙烯基硅氧烷中,再配以增强剂、硫化剂等,经模压硫化制得导热硅橡胶。研究了导热填料种类、石墨的表面改性和用量以及石墨与炭黑的复配对硅橡胶导热性和力学性能的影响。结果表明,在用量相同的情况下,导热填料的导热系数越高,其填充硅橡胶的导热性越好,且硅橡胶的导热系数随导热填料用量的增加而增大。石墨的表面改性改善了石墨与硅橡胶的界面相容性,使硅橡胶的力学性能和导热性都得到提高。不同粒径及颗粒形态的炭黑与石墨复合可改善硅橡胶的导热性和力学性能,导热硅橡胶的拉伸强度和扯断伸长率随复合填料中炭黑用量的增加而提高,当石墨与炭黑质量比为25/5时,硅橡胶的导热系数最高,综合性能较好。     

Resistivity and thermal reproducibility of carbon black and metallic powder filled silicone rubber heaters

Flexible heaters were prepared by extruding platinum‐catalyzed silicone rubber composites with conductive carbon black (CB) and metallic fillers. The conductor resistivity of the extruded heaters decreased in order of conductive titanium dioxide (TiO₂) > aluminum powder ≈ zinc powder > copper powder. Thermoelectric switching phenomena were investigated for the silicone rubber/CB/metallic powder systems. The positive temperature coefficient effect was dependent mainly on the CB content rather than on the content of the metallic powders. Resistivity and thermal reproducibility of the extruded heaters were also investigated by periodically applying AC voltage of 110 V. The heaters containing copper and TiO₂ powders exhibited excellent electrical reproducibility. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1122–1128, 2005     

Effect of crosslinking on the conductivity of conductive silicone rubber

We investigated the effect of polyvinylsilicone oil (C gum) as a crosslinker and 2,5‐bis(tert‐butyl peroxy)‐2,5‐dimethyl hexane (DBPMH) as a curing agent on the conductivity of conductive silicone rubber with two different kinds of conducting mechanisms. The experimental results show that the volume resistivity of conductive silicone rubber changed with its degree of crosslinking. When the carbon black loading was 25 parts per hundred rubber (phr) and a completely continuous conducting network had not formed, the volume resistivity of the vulcanizates decreased with increasing crosslink density. The volume resistivity of the vulcanizate with a suitable amount of C gum decreased to 53%, and the tensile strength increased by 0.8 MPa compared to the vulcanizate without C gum. When the carbon black loading was 40 phr and a completely continuous conducting network had formed, the crosslink density of vulcanizates changed as the amount of DBPMH changed. The volume resistivity of vulcanizates first decreased and then increased with increasing crosslink density. There was a valley value in the resistivity–crosslink density curve. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3471–3475, 2003     

加成型导热电子灌封硅橡胶的研究

以α,ω-二乙烯基聚二甲基硅氧烷为基胶,配合石英粉、氧化铝、含氢硅油、Pt催化剂等,制成加成型导热电子灌封硅橡胶.研究了导热填料及其用量对加成型导热电子灌封硅橡胶性能的影响.结果表明,石英粉与氧化铝填料都可以提高液体硅橡胶的导热性能,但是随着填料的粒径增大,硅橡胶的机械性能逐渐下降;对比两种导热填料,石英粉体系液体硅橡...     

导热填料对NR/BR硫化胶的生热和导热的影响

研究了氧化锌、炭黑、石墨等几种导热填料对NR/BR硫化胶的生热和导热性能的影响。结果表明,提高氧化锌的用量可以减小硫化胶的损耗和压缩温升、提高导热系数;增加炭黑用量虽然提高导热系数,但炭黑的Payne效应、损耗和压缩温升等动态性能大幅度增加,表现出明显的逾渗现象,而导热系数、定伸应力、硬度等静态性能增加幅度较小;大粒径炭黑有利于提高硫化胶的导热系数、降低损耗和压缩温升,高结构度炭黑虽能提高导热系数,但是损耗和压缩温升增加。配方中加入氧化铝、氢氧化铝、石墨、煤灰、铝粉后,硫化胶的力学性能较差,Payne效应较弱,损耗和压缩温升明显降低,含有铝粉或石墨硫化胶的导热系数较高。     

Novel heat‐conductive composite silicone rubber

The silicone rubber with good thermal conductivity and electrical insulation was obtained by taking vinyl endblocked polymethylsiloxane as basic gum and thermally conductive, but electrically insulating hybrid Al₂O₃ powder as fillers. The effects of the amount of Al₂O₃ on the thermal conductivity, coefficient of thermal expansion (CTE), heat stability, and mechanical properties of the silicone rubber were investigated, and it was found that the thermal conductivity and heat stability increased, but the CTE decreased with increasing Al₂O₃ fillers content. The silicone rubber filled with hybrid Al₂O₃ fillers exhibited higher thermal conductivity compared with that filled with single particle size. Furthermore, a new type of thermally conductive silicone rubber composites, possessing thermal conductivity of 0.92 W/mK, good electrical insulation, and mechanical properties, was developed using electrical glass cloth as reinforcement. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2478–2483, 2007     

橡胶导热助剂的优选

探讨导热助剂和填料对胶料导热性能的影响。结果表明：导热增强剂TB-1对橡胶的补强作用和导热效应优于氧化锌、三氧化二铁、三氧化二铝,可以用作导热型补强助剂;用于轮胎胎侧胶和胎体胶,可以提高胶料的导热性能,对胶料物理性能影响不大;用于水胎胎体胶,可以提高水胎传热速度,缩短硫化时间,提高硫化效率,降低硫化能耗。不同种类的炭黑对胶料导热性能影响不同;炭黑用量增大,胶料的导热系数增大。     

Thermal conductivity of silicone rubber filled with ZnO

Thermal conductivities of silicone rubber filled with ZnO in a wide volume range were measured in order to study the effect of formed conductive particle chains on thermal conductivities. With the increasing of content of ZnO particles in silicone rubber, the amount of formed conductive chains increases and the conductive chains tend linearly to increase the thermal conductivity of the composite. The experimental results obtained were also analyzed using the Nielsen and Agari models to explain the effect of ZnO filler on the formation of thermal conductive networks. Thermal conductivities of a polymer filled with high volume content of particles evidently increased with the adding of small size fillers. The scanning electron microscopy (SEM) showed that percolation threshold has been reached at 31.4 vol% ZnO filler loading, and the hybrid fillers are more densely packed than single fillers in the silicone rubber matrix. There occurs a positive temperature coefficient (PTC) phenomenon in thermal resistance in composites of silicone rubber filled with ZnO. POLYM. COMPOS., 28:125–130, 2007. © 2007 Society of Plastics Engineers     

Effects of crosslinking reaction and extension strain on the electrical properties of silicone rubber/carbon nanofiller composites

Stretchable conductive silicone rubber (SR) composites are important in wearable electronic devices and the crosslinking of SR composites is necessary for their applications. But the effect of the crosslinking reaction on the electrical conductivity of SR composites is rarely reported. In this article, the effect of crosslinking reaction on the electrical conductivity of SR composites filled with conductive carbon black, carbon nanotubes, and graphene are studied. The crosslink density of SR composites increases with increasing curing time, but the electrical conductivity decreases sharply at the early stage of crosslinking, especially for SR/conductive carbon black composite, which is ascribed to the reaggregation of conductive nanofillers in SR during the crosslinking process. The elastic modulus of the three SR composites gradually increases while the elongation at break decreases with increasing curing time, and the SR/carbon black composite shows ultra-high elongation at break (1578%). In addition, SR/graphene composite is more sensitive to the extension strain than SR/carbon black and SR/carbon nanotubes composites, and its gauge factor is 414 at the strain ranges of 3–25%. This research work brings a new method to optimize the crosslinking structure of conductive SR composites.     

填料改性氟橡胶的制备及性能研究

针对氟橡胶加工性能不良、耐磨性差、价格昂贵的问题,以耐磨炭黑和白炭黑为增强填料,二硫化钼为减磨填料对其进行改性,考察了不同填料种类及用量对氟橡胶力学及耐磨性能的影响。结果表明：炭黑和白炭黑用量分别为25份和20份时硫化胶的综合性能最优,在此基础上,随着二硫化钼用量的增加,炭黑增强氟橡胶的摩擦系数减小,耐磨性提高,但力学性能有所降低;对于白炭黑增强氟橡胶体系,随着二硫化钼用量增大,耐磨性和力学性能均先减小后增大。