含双噻唑基聚合物的合成及电流变性能研究

采用2，2’-二氨基-4，4’-双噻唑与联苯胺合成一种含有双噻唑基的共轭聚合物，通过红外、扫描电镜、热重分析等测试了该物质的结构及热稳定性等，并通过将聚合物分别分散在硅油和溴代二苯甲烷中制备电流变体，测试其电流变性能。结果表明：含双噻唑基的共轭聚合物作为电流变体的分散相表现出了良好的电流变性能，同时发现分散相和分散介质的密度相近时有利于电流变性能的提高。     

壳聚糖电流变体的导电特性

电流变体是由高介电颗粒分散在低介电油相中组成的悬浮液,在电场作用下,其表观粘度急剧增大甚至发生固化,这种转变过程速度快（达毫秒级）而且是可逆的［１］．由于这种独特的电场响应性,电流变体有广阔的工程应用前景．但电流变体在显示电流变效应的同时也表现出复杂...     

聚电解质电流变效应中的Ec及其产生机理的研究

为了深入研究电流变体中电压阀值 (Ec)产生的机理 ,实验设计了一种全新的测试方法饱和电压法 ,并用此方法明确地证实了电压阀值 (Ec1和Ec2 )的存在同时对此作出了解释 ;而且还对两种典型的电流变模型在不同电流变体中的适用性作出了定义。计算机模拟的结果分别给出了两个对应于电压阀值Ec1和Ec2的序参量 φ1 =1 5和 φ2 =4 5。     

分散介质和表面活性剂对γ-Fe_2O_3/聚丙烯酸锂复合微粒电流变效应的影响

采用反乳液聚合方法制备了γ－Ｆｅ２Ｏ３／聚丙烯酸锂复合微粒，将其悬浮分散于硅油、液体石腊等绝缘介质中形成电流变体。考察了在直流和交变电场作用下分散介质的种类、表面活性剂种类及用量等对复合微粒电流变效应的影响。     

蒙脱土/二氧化钛复合颗粒电流变液材料的制备及其性能

利用溶胶-凝胶法制备了一种新型的蒙脱土/二氧化钛(MMT/TiO_2)复合电流变 颗粒材料，FT-IR，XRD，SEM分析表明TiO_2以纳米晶的形态包覆于蒙脱土表面。电 流变性能测试表明，MMT/TiO_2复合颗粒的电流变效应比纯蒙脱土电流变液有显著 提高，当颗粒体积分数为25%，直流电场强度为3kV/mm时，TiO_2质量分数为22.7% 的MMT/TiO_2复合颗粒电流变液的静态屈服应力达8.3kPa，此值约为纯蒙脱土电流 变液的4倍。同时发现TiO_2包覆量对电流变效应有重要影响。     

核壳型聚苯胺/钛酸钡的结构及其电流变性能

用改进的溶胶-凝胶法制备了核壳型聚苯胺/钛酸钡复合微粉,通过TEM及FT-IR分析表征了其形貌及微观结构,用复合微粉与氯化石蜡油配制成无水电流变(ER)液,研究其不同膜厚核壳粒子的电流变性能.研究结果表明,聚苯胺/钛酸钡复合粒子配置成的电流变液的电流变性能较纯聚苯胺的为强;钛酸钡的涂层厚度对复合粒子电流变性能有重要影响;并在d=20 nm时获得最佳电流变性能.     

电流变阻尼器的抗冲击性能研究

从理论和试验两个方面研究了所设计的电流变阻尼器在大冲击下的抗冲击性能,分析了电流变液性能与阻尼器结构参数对抗冲击性能的影响.认为采用高性能的电流变液体及改变结构参数,都可以使电流变阻尼器的高速缓冲性能提高.电流变液流速对电流变液的屈服应力影响显著,其值随流速的增加按指数规律减小.从定性、定量两个方面分析了电流变阻尼器作为阻尼器效果不明显的原因为:由电流变效应引起的阻尼力在整个液压阻力中所占比例太小,不能通过改变电压来使液压阻力具有很大的调节可控范围.     

石墨烯/聚合物纳米复合电流变材料

电流变智能流体在外电场刺激下能快速可逆地改变自身流变性能,具有重要技术应用价值.传统的基于微米颗粒的电流变流体易于沉降并且电致屈服强度不高限制了技术应用,最近基于纳米颗粒的非传统电流变材料研究受到重视,特别是具有各向异性形貌的纳米颗粒悬浮液被发现具有明显增强的电/磁流变效应.本文介绍了最近基于石墨烯的二维纳米复合电流变材料的研究进展,主要包括石墨烯/半导聚合物、石墨烯/极性聚合物、石墨烯/碳等几种典型的电流变材料的制备、结构和电流变行为.研究表明利用石墨烯独特的二维纳米结构、优异的电学和热学性质可能为制备新颖的高性能纳米电流变材料提供途径。     

沸石电流变液材料的研究

系统地研究了沸石的由离子类型、数目、骨架的孔道大小和结构特性对沸石电流变液性能的影响. 证实了阳离子在电场中的迁移所引起的晶粒极化是Y，A和M等沸石电流变特性的基础，指出了较大的孔径和具有足够多易迁移的阳离子是该类沸石具有较好电流变性的的前提．根据NaZSM－5沸石在高电场中与其它沸石表现不同，具有屈服应力大而漏电流小的特点，提出了沸石晶粒极化还可能存在的另一种新的晶格变形机理．     

接枝共聚改性氧化淀粉及电流变性研究

通过自由基接枝共聚的方法，合成了改性的氧化淀粉-BA—MAA—Gd共聚物，采用红外光谱、扫描电镜、同步热分析、x射线粉末衍射等方法对产物进行了结构表征。用接枝物制备了电流变液，测定了在不同接枝物含量和电场强度下体系的电流变效应。实验结果表明：该电流变液体系的剪切应力随着电场强度的增大而增大；而在相同电场强度下，剪切应力则随电流变液中接枝物含量的增加而增大。     

Differences in the electrorheological response of a particle suspension under direct current and alternating current electric fields

We have observed an unusual reduction of shear stress with increasing shear rate under direct current electric fields, for an electrorheological fluid composed of sulfonated poly(styrene-co-divinylbenzene) particles dispersed in silicone oil. At all shear rates, the shear stress under the electric field is larger than that in the absence of the field, indicating that there is still some field-induced agglomeration of the particles. In contrast, the behavior under alternating current electric fields is the Bingham-fluid-type response commonly observed with electrorheological fluids. It is suggested that the conventional dipole–dipole interaction approach based on simplified microstructural models would be unable to explain these phenomena. Received: 27 November 2000 Accepted: 22 May 2001     

二氧化硅负载胺丙基硅烷电流变流体

研究用二氧化硅负载胺丙基三乙氧基硅烷［ＮＨ２（ＣＨ２）３Ｓｉ（ＯＥｔ）３］作为分散颗粒，制备无水型的电流变（ＥＲ）流体．考察电场强度（Ｅ）、剪切速率（γ·）、分散颗粒含量、分散介质种类以及极性小分子等因素对ＥＲ流体流变性能的影响．结果发现，以硅油为分散介质，含分散颗粒为１５％（ｇ／ｍｌ）的流体，不添加任何活化剂，在γ·为８０６６ｓ－１时，Ｅ从０升至１６６６ｋＶ／ｍｍ，流体的表现粘度（ηａ）从０３９６Ｐａ．ｓ增大到１６６６８Ｐａ．ｓ．γ·提高，ηａ降低．分散颗粒含量增加，ηａ增大．用硅油作分散介质，ＥＲ效应比用矿物油或石蜡油显著．加入极性小分子苯胺，可以增强流体的ＥＲ效应，但随着苯胺含量增多，漏电流密度也增大．     

Effect of polymerization temperature on polyaniline based electrorheological suspensions

As one of the intrinsically polarizable materials used in electrorheological (ER) fluid, polyaniline was synthesized by the chemical oxidation of aniline with ammonium peroxysulfate. ER fluids were prepared by dispersing polyaniline particles in silicone oil, and their rheological properties were measured. The effect of the polymerization temperature of polyaniline on its ER characteristics was investigated. ER fluids with polyaniline particles synthesized at −10°C (PA-10) showed the best ER performance (yield stress) compared with those synthesized at higher temperatures. A difference in the flow behavior of the ER fluids was also investigated through the dielectric spectra of ER fluids. Received: 24 March 1988 Accepted: 3 August 1998     

高岭土／羧甲基淀粉复合颗粒的制备及其协同电流变效应

通过二次插层取代法，以二甲基亚砜为前驱体，羧甲基淀粉二次插层取代制备 了高岭土/羧甲基淀粉纳米复合材料。结合XRD，FTIR，SEM和EDS等测试手段对复合 材料的结构进行了表征。研究结果发现，羧甲基淀粉经过二次插层取代引起了高岭 土片层之间的剥离，形成剥离型纳米复合材料。该复合材料制备成电流变液出现了 较大的协同效应，具有很好的电流变行为，并发现电流变性能与复合物中羧甲基淀 粉的含量有密切关系。     

聚N-甲基苯胺/蒙脱土纳米复合材料的合成及其协同电流变效应

用插层聚合法制备了聚N 甲基苯胺 蒙脱土纳米复合材料微粒 ,通过IR、XRD及TEM对其结构进行了表征 .观察发现聚N 甲基苯胺插入蒙脱土层间后 ,蒙脱土片层间距由 0 96nm扩大至 1 34nm .将其分散在甲基硅油中 (2 0wt% )配制成无水电流变液 ,该复合材料表现出显著的协同效应 ,具有较好的电流变行为 .实验表明在电场作用下聚N 甲基苯胺 蒙脱土纳米复合材料的电流变效应比聚苯胺、蒙脱土都有显著提高 ,在 3kV mm(DC ,74 5s- 1 )时 ,剪切强度达 6 0kPa ;同时抗沉降性极好 ,静置 6 0天沉淀率小于 3% .介电性能测试表明聚N 甲基苯胺 蒙脱土纳米颗粒的介电常数和介电损耗较蒙脱土和聚N 甲基苯胺明显提高 ,电导率也达到了最佳范围 .     

Electrorheological Moment Amplifier

An electrorheological moment amplifier is developed and its work principle and structure characteristics are explained. Then, we research the effects of structural parameters on performance of mechanism and present optimization design methods and control methods. With a view of enhancing the amplification coefficient or increasing the speed of dynamic response, the expectation values of objectives and the weight are obtained and the amplifier with good performance could be designed. In this paper, the parabolic relation between moment amplified and electric field is decided by experimental fit method. And step and pulse electric field signals are used to study the dynamical properties of the device. As the result of experiments, it is confirmed that the electrorheological moment amplifier has good dynamic performance through optimization design methods.     

聚苯胺类电流变体的稳态剪切流动分析

对聚苯胺、及聚苯胺/聚丙烯酸盐复合粒子的稳态剪切流动行为进行了综合考察.结果表明, 在交流电场下,电流变体的剪切应力和剪切速率的关系符合Bingham流体形为.并对此现象进行了分析,提出用非理想塑性体的新模型来描述交流电场下聚苯胺类电流变体的稳态剪切流动.     

A new approach of enhancing the shear stress of electrorheological fluids of montmorillonite nanocomposite by emulsion intercalation of poly-N-methaniline

Poly-N-methaniline/montmorillonite (PNMA-MMT) nanocomposite particles with high dielectric constant as well as suitable conductivity were synthesized by an emulsion intercalation method and characterized by FT-IR, XRD, and TEM spectrometry, respectively. The electrorheological (ER) properties of the suspensions of PNMA-MMT particles in silicone oil (20 wt%) were investigated under DC electric fields. It was found that the shear stress of poly-N-methaniline/montmorillonite electrorheological fluid (ERF) is 6.0 kPa in 3 kV/mm (74.5 s(-1)), which is 3.6 times that of electrorheological fluid at zero field, and also much higher than that of pure poly-N-methaniline (PNMA) and montmorillonite (MMT). In the range of 10-90 degrees C, the shear stress changes slightly with the temperature. The sedimentation ratio of PNMA-MMT ERF was about 97% after 60 days. Furthermore, the dielectric constant of PNMA-MMT nanocomposite was increased 3.74 times that of PNMA and 1.99 times that of MMT at 1000 Hz, the dielectric loss tangent also increased about 1.58 times that of PNMA. It is apparent that the notable ER effect of PNMA-MMT ER fluid was attributed to the prominent dielectric property of the poly-N-methaniline/montmorillonite nanocomposite particles.