邻苯二甲酸二辛酯复合锂基润滑脂的研制及其性能表征

采用合成酯类油邻苯二甲酸二辛酯作为基础油合成复合锂基润滑脂,并对其进行各项性能指标分析,探究其综合性能及应用。制备的润滑脂具有很高的滴点和胶体安定性及较好的低温性能。热重分析表明将邻苯二甲酸二辛酯制备成脂后,其热稳定性有所提高.低温DSC表明成脂后,其结晶温度与酯油相同,仍然保持较好的低温性能。扫描电镜结果表明润滑脂形成致密的皂纤维结构。     

复合锂基润滑脂的基础研究

锂基润滑脂是由天然脂肪酸锂皂稠化中等粘度的矿物润滑油或合成润滑油制成。复合锂基润滑脂具备了锂基润滑脂优良的机械安定性、胶体安定性和氧化安定性,还具有滴点高等高温使用性能。利用硼酸或己二酸为复合剂合成了两种复合锂基润滑脂,并利用差动热分析仪对其进行滴点的测定,得到最佳配方。研究表明,硼酸或己二酸对提高复合锂基润滑脂脂滴点可以起到一定的的作用,但用一步法的生产工艺更适合硬脂酸／己二酸复合锂基脂的生产。     

热磁耦合作用下磁流变脂剪切稳定性及其机理

磁流变器件内部介质均面临热磁耦合、频繁剪切等复杂工况,剪切稳定性是磁流变介质实现持久服役的重要指标。本文以实验室制备的磁流变脂为研究对象,基于流变学、磁学性能分析结果探究了热磁耦合作用下磁流变脂剪切稳定性变化规律及其机理。研究结果表明,温度和磁场强度发生变化时,磁流变脂流变性能也发生了较为显著的变化。触变性分析与连续剪切结果显示热磁耦合作用下磁流变脂总体保持着较好的剪切稳定性,基载液润滑脂皂纤维结构和磁链的交互作用将会对磁流变脂剪切稳定性产生影响。在较低温度、较弱磁场强度下,皂纤维结构是磁流变脂流变学性能影响的主导因素,剪切稳定性良好;在较高温度、较强磁场强度下,皂纤维缠结程度降低而磁链强度增强,磁链结构在磁流变脂流变学性能影响中占主导因素,剪切稳定性良好;在从皂纤维影响占主导变化为磁链影响占主导过程中,皂纤维剪切破坏时磁性颗粒被释放出来,因磁场的影响,磁性颗粒无法及时分散至皂纤维内部,最终致使磁流变脂剪切稳定性变弱。     

基于二羟基硬脂酸的复合锂基润滑脂性能研究

采用自制的9,10-二羟基硬脂酸(DHSA)与12-羟基硬脂酸(HSA)为原料,使用直接皂化法制备三组分的复合锂基润滑脂,幵研究了DHSA和HAS的摩尔比及中小分子酸种类对所制润滑脂稠度、高温性、胶体安定性以及流变性能等的影响。结果表明,十二烷二酸制备的复合锂基润滑脂的各项性能较为优异。     

水焦浆的流变特性与壁面滑移效应

在浆体流动试验系统上采用不同管径的直管考察了水焦浆的流变特性以及壁面滑移效应对水焦浆流动特性的影响。采用Tikhonov 正则化方法确定了水焦浆的真实流变特性和壁面滑移特性。结果表明：浓度为59.8%的水焦浆随剪切速率增大呈现由伪塑性流体到胀塑性流体的转变,浓度增加,水焦浆变为单一的胀塑性流体,当浓度达到63.4%时,水焦浆表现为由胀塑性流体到伪塑性流体的转变;水焦浆的流变特性对滑移速度的变化趋势具有较大影响,滑移速度在水焦浆为胀塑性流体时随剪切应力增加呈加速增加,水焦浆为伪塑性流体时滑移速度随剪切应力的增长速率变化不明显;滑移贡献率的变化趋势迟滞于流变特性曲线。     

由扩散泵硅油高沸物制备高温润滑脂的性能

以制扩散泵用硅油的高沸物为基础油、脂肪酸锂单皂或脂脂酸锂复合皂为稠化剂,制备出2种有机硅高温润滑脂。测试表明,两种润滑脂的理化指标都不错。脂肪酸金属皂能够稠化高沸物,其中用脂肪酸锂基单皂制备的有机硅润滑脂能在温度不高于120℃条件下使用;而用脂肪酸复合锂皂制备的有机硅高温润滑脂可在200℃以下使用,短期使用温度可达250℃。     

PVC板料渐进成形润滑方式研究

采用数控渐进成形工艺,利用高速转动工具头与聚氯乙烯(PVC)板料间局部摩擦热以成形变角度圆锥制件,研究了皂液、40号机油、聚四氟乙烯脂、锂基高温润滑脂、水等5种不同润滑剂对PVC板料渐进成形性能的影响,利用多功能摩擦磨损试验机测试了5种不同润滑剂的摩擦系数。结果表明,润滑剂对成形制件最大成形深度和最大成形角度的影响程度由大到小为:皂液40号机油聚四氟乙烯脂水锂基高温润滑脂。水作润滑剂时,随摩擦时间增加,摩擦系数由小增大,基底暴露,起屑严重,制件表面粗糙;皂液、40号机油、聚四氟乙烯脂、锂基高温润滑脂做润滑剂时摩擦系数相差较小,制件表面有轻微刀痕,表面质量相差较小。与其它润滑剂相比,皂液作润滑剂时PVC板料具有较好的渐进成形性能和表面质量。     

膨润土-复合锂基润滑脂的制备及性能研究

为了在提高复合锂基润滑脂的综合性能下同时减少皂基润滑脂的含量,采用矿物油(68#导轨油)为基础油,以12-羟基硬脂酸、癸二酸、有机膨润土、单水氢氧化锂为稠化剂原料,制备了膨润土-复合锂基润滑脂。结果表明:当添加30%,膨润土含量为20%的膨润土润滑脂时,膨润土-复合锂基润滑脂综合性能最好,其滴点为255. 5℃、锥入度为269/10-1mm、钢网分油为1. 24%。扫描电镜表明膨润土润滑脂与复合锂基润滑脂之间产生的分子间氢键可以使皂纤维产生更加致密的结构,出现的类似于"干木耳"状的结构,增加了皂纤维与基础油的接触面积,从而增加了与基础油之间的作用力。     

复合锂基润滑脂的研究进展

复合锂基润滑脂具有良好的高温多效性能,自发明以来持续受到广泛研究和应用.同时复合锂皂良好的基础油稠化能力和添加剂感受性,使其可以制备满足各种工况要求的润滑脂.综述了复合锂基脂组成和制备工艺对其性能及结构的影响,探讨了复合锂基脂成脂机理,并对复合锂基润滑脂的未来发展进行了展望.     

喷气燃料热氧化安定性的研究综述

复合锂基润滑脂具有良好的高温多效性能,自发明以来持续受到广泛研究和应用.同时复合锂皂良好的基础油稠化能力和添加剂感受性,使其可以制备满足各种工况要求的润滑脂.综述了复合锂基脂组成和制备工艺对其性能及结构的影响,探讨了复合锂基脂成脂机理,并对复合锂基润滑脂的未来发展进行了展望.     

Influence of soap/polymer concentration ratio on the rheological properties of lithium lubricating greases modified with virgin LDPE

The main goal of this work was to study the feasibility of using a low-density polyethylene (LDPE) as additive to improve the rheological properties of lithium lubricating greases. The combined effect that both soap and LDPE concentrations exerts on the rheology of lithium lubricating greases and its relationship with grease microstructure were studied according to an experimental design based on the response surface methodology (RSM). Different lubricating grease formulations were manufactured by modifying lithium 12-hydroxystereate and LDPE concentrations. Small-amplitude oscillatory shear (SAOS) and viscous flow measurements, as well as mechanical stability tests, were performed. In addition to these, environmental scanning electronic microscopy (ESEM) was used to determine grease microstructure. LDPE was found to be a useful additive to modify grease rheology, acting as filler in the entangled soap network. The values of both apparent viscosity and linear viscoelasticity functions increase with soap and LDPE concentration. However, the addition of LDPE distorts soap microstructural network, yielding greases with lower relative elastic characteristics.     

重载车辆润滑脂流变及润滑特性对比分析

考察了四种重载车辆润滑脂的流变学性能和摩擦学性能,分析了基础油的种类和粘度、稠化剂的种类和含量以及增粘剂等参数在不同温度下对润滑脂流变学性能的影响;使用流变仪的"三板球"测试组件对四种润滑脂摩擦学性能进行测试,考察不同压力和速度下润滑脂摩擦系数的变化情况。结果表明:在流变学测试中,LX-4和LX-2润滑脂表现出了较好的高温性能,说明这两种润滑脂在高温密封性能和高温粘附性上表现优异,其中LX-4在高低温范围都显示出优良的润滑性能。在摩擦学测试中,LX-2润滑脂表现出较低的摩擦系数,特别是在50 N高压区,LX-2表现出更容易进入薄膜润滑区,润滑膜形成更加容易,摩擦系数下降较快。     

Investigation of thermal degradation of polyethylene–polypropylene-based grease

Thermal degradation of polyethylene–polypropylene-based lubricating grease was studied in a differential scanning calorimeter under static air atmosphere, while weight loss with increase in temperature under inert atmosphere of nitrogen gas was recorded thermogravimetrically. The polymer-based grease exhibited higher thermal stability when compared to that of a soap-derived multipurpose lubrcating grease based on lithium 12-hydroxystearate.     

超声波改善二硫化钼润滑脂性能的研究

研究了超声波对二硫化钼润滑脂性能的影响,结果表明,超声波能通过声流和声空化作用对复合锂基润滑脂中的二硫化钼进行微观均化,进而提离润滑脂的抗磨减摩性能。     

Recycled and virgin LDPE as rheology modifiers of lithium lubricating greases: A comparative study

In this work, a new application for recycled low‐density polyethylene (LDPE), as rheology modifier of standard lithium lubricating grease formulations, was studied. The effectiveness of this additive was compared with that achieved with a virgin LDPE. With this aim, both types of polymers were added to the formulation during the manufacturing process of greases, following the same standard protocol, to reinforce the role of the thickening agent, the lithium 12‐hidroxystearate. The effect that both lithium soap and LDPE concentrations exert on the rheology of lubricating grease formulations and its relationship with grease microstructure were discussed. Lubricating greases were rheologically characterized through small‐amplitude oscillatory shear and viscous flow measurements. In addition to these, scanning electron microscopy observations and mechanical stability tests were also carried out. In all cases, an increase in soap concentration yields higher values of apparent viscosity and linear viscoelasticity functions. On the other hand, the values of the rheological functions obtained for recycled LDPE‐based lubricating greases are, in general, higher than those obtained for virgin LDPE‐based grease formulations. However, the structural skeleton developed in greases containing recycled LDPE demonstrates less resistance to severe working conditions, showing lower mechanical stability than virgin LDPE‐based grease formulations. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Preparation of High-Density Aqueous Suspensions and the Molding of Preforms from Lithium Aluminosilicate Glass

Preparation of high-density, sedimentation-stable aqueous suspensions and preforms, based on lithium aluminosilicate glass, using a method of slip casting into porous molds is reported. Properties of slips under different conditions of grinding and stabilization are considered depending on the grinding-body-to-material weight ratio, the amount of dispersion medium added, and the technology for processing lumpy raw material. The wall thickness growth rate in preforms is measured in relation to slip parameters. Measures that would enable control over slip properties with a view to optimizing the slip casting technology are proposed.     

润滑脂流变性影响因素研究现状

润滑脂由于其复杂而独特的流变性能,近年来受到了学界的广泛关注。学者们选用一系列流变参数来定性定量描述润滑脂的流变性能。润滑脂组分、工作条件及制备手段的变化常常会影响和改变润滑脂的流变参数。综述了温度,稠化剂结构、含量及粒度,基础油,添加剂及填料,制备条件,微观结构等因素对润滑脂流变参数的影响情况,总结了润滑脂流变学发展中存在的问题,并对润滑脂流变学未来的发展进行了展望。     

硫酸钙晶须作为润滑脂添加剂的摩擦学性能

通过四球摩擦磨损实验,考察了不同粒径、不同添加量的硫酸钙晶须在锂基润滑脂中的摩擦学性能,应用光学显微镜观察钢球磨斑表面。结果表明,在一定的摩擦学环境下,添加质量分数3%的球磨6 h的硫酸钙晶须能够显著提高锂基润滑脂的抗磨减摩性能。