地沟油制备有机稀土化合物及其摩擦学性能研究

以地沟油为原料,制备了一种油溶性有机稀土化合物(ORE),并通过红外光谱和等离子发射光谱对其化学结构和元素组成进行了表征。用万能摩擦磨损试验机考察了有机稀土化合物在液体石蜡中的摩擦学性能,结果表明:有机稀土化合物作为润滑添加剂具有比ZDDP更好的抗磨减摩性能,有望作为新型的环境友好型润滑添加剂在工业实际中得到应用。当基础油中加入1.0%ORE时,其减摩性能和抗磨性能分别提高23%和34%,其承载能力是基础油的2.4倍。分析认为有机稀土化合物在摩擦过程中形成的含稀土的边界润滑膜可能是其具备良好极压抗磨和减摩效果的主要原因。由地沟油制备环境友好型润滑添加剂,是探索地沟油资源化利用技术的有益尝试,具有良好的推广应用前景。     

稀土化合物的润滑性能

通过摩擦磨损试验考察了Ｌａ，Ｐｒ，Ｓｍ，Ｅｕ和Ｇｄ的二烷基二硫代磷酸盐（ＲＥＤＤＰ）、二烷基膦酸盐（ＲＥＤＰＥ）和三烷基磷酸盐（ＲＥＴＡＰ）３种类型１５种稀土化合物的抗磨减摩性能。结果表明，稀土化合物具有较好的抗磨减摩性能，润滑性能的优劣顺序为：ＲＥＤＤＰ＞ＲＥＤＰＥ＞ＲＥＴＡＰ，对每一种类型的稀土化合物而言，润滑性能的优劣顺序为：Ｓｍ＞Ｌａ＞Ｐｒ＞Ｇｄ＞Ｅｕ。     

环烷酸铅和烷基水杨酸铅的微波原位合成及其摩擦学性能

在液体石蜡中采用微波技术原位合成了油溶性环烷酸铅(LN)和十二烷基水杨酸铅(LAS).在高速低负荷(r=1500±10 rpm、 P=196～392 N)和低速高负荷(r=300±10 rpm、 P=800 N)两种条件下,用四球摩擦磨损试验对LN、 LAS和对应的羧酸进行了摩擦学性能评价,用往复式摩擦试验机考察了LN和LAS抗磨减摩性能.结果表明: LN具有良好的抗磨减摩性能和中等的极压性能,且各项摩擦学性能指标均好于LAS.为弄清其作用机理,从分子结构分析了产生摩擦学性能差异的原因,并用SEM及XPS研究了磨斑表面.结果发现: 摩擦过程中, LN和LAS都能在摩擦副表面形成吸附膜且部分吸附膜发生摩擦化学反应产生了铅氧化物转化膜,但所形成的吸附膜和转化膜厚度不同.     

含纳米稀土、铁复合粒子润滑油的摩擦学性能

选择了吐温(Tween)-60、司本(Span)-20、司本(Span)-80和聚醚表面活性剂,配制了纳米稀土(RE)和铁粒子的复合润滑油.采用透射电子显微镜(TEM)观察、测定了纳米稀土、铁粒子形貌和粒径.采用磨损试验机测试了含纳米稀土、铁复合粒子润滑油的摩擦学性能.结果表明纳米稀土与纳米铁粒子比例为11,总浓度为0.6%时该润滑油具有最佳的抗磨、减摩性能.并探讨了其抗磨、减摩机制.     

磷酸镧和二烷基二硫代磷酸锌及其复合添加剂对通用锂基脂摩擦学性能的影响

合成了稀土化合物磷酸镧，利用四球摩擦磨损试验机考察了磷酸镧，商品添加剂二烷基二硫代磷酸锌及两者的复合添加剂对通用锂基脂摩擦学行为的影响，用扫描电子显微镜和X射线光电子能谱仪（XPS）观察分析了钢球磨损表面形貌及其元素的化学状态。研究结果表明：磷酸镧和二烷基二硫代磷酸锌均可增加通用锂基脂的承载能力，磷酸镧可提高锂基脂的减摩抗磨能力，二烷基二硫代磷酸锌对基础脂的减摩抗磨性能的作用效果不稳定。含上述添加剂的锂基脂在摩擦副表面发生化学吸附或摩擦化学反应，生成由锂基脂和添加剂共同作用形成的边界润滑膜，从而改善锂基脂的润滑性能。     

二烷基二硫代磷酸钕的摩擦磨损性能研究

用自制的二烷基二硫代磷酸和NdCl3为原料，通过交换反应制备了二异辛基二硫代磷酸钕和二异丙基二硫代磷酸钕，并鉴定了其结构，以四球实验比较了所合成的两种二烷基二硫代磷酸钕作为抗磨减摩剂的抗磨减摩性能，并与现在普遍使用的抗磨剂ZDDP进行了比较。以电子衍射X射线能谱（EDXA）分析了经四球机实验摩损10s后的蚀球表面元素组成，初步认证了稀土元素扩渗进入摩擦副表面是此类稀土配合物具有比ZDDP更好的抗磨减摩作用的原因之一。     

一种高硫的噻二唑衍生物的摩擦学性能研究

合成了一种高硫含羟基和黄原酸的噻二唑衍生物(ESP),利用四球摩擦磨损试验机考察了其在Corda3970基础油中的摩擦磨损性能,表明所合成的添加剂能够有效的提高Corda 3970基础油的极压和抗磨性能,并且在一定的浓度范围内随着浓度的增加,其抗磨减摩性能增加。通过扫描电镜(SEM)分析了钢球表面形貌及元素分布,发现其主导作用的是边界膜中存在S、O、N活性元素,它们形成复合膜是添加剂具有摩擦学性能的主要原因。     

双/三氮杂冠醚化合物的合成及其作为摩擦改进剂的性能研究※

现代汽车工业的发展以及环保法规的日益严格对车用润滑油的性能提出了更高要求, 摩擦改进剂在提高发动机油减摩性能及燃油经济性方面发挥着重要作用. 有机钼化合物作为目前使用最为广泛的摩擦改进剂, 会增加油品热氧化沉积物的生成, 且油品氧化会导致其减摩性能下降. 针对摩擦改进剂所存在的诸如有害元素、灰分及活性吸附位点有限等问题, 设计并合成了两种双/三氮杂冠醚化合物, 将活性氮原子及长链烷基引入冠醚结构中以提高吸附性能和油溶性, 并研究其作为摩擦改进剂的减摩和抗磨性能. 结果表明, 所合成双/三氮杂冠醚能有效降低油品的摩擦系数和磨损率, 其中含有吡啶结构的三氮杂冠醚表现出更优的摩擦学性能, 可使摩擦系数和磨损率相对于基础油分别降低8.8%和42%. 机理分析表明, 所合成的双/三氮杂冠醚化合物能够在钢表面发生不同程度的吸附, 并进一步发生摩擦化学反应形成润滑保护膜, 防止滑动表面微凸体的直接接触进而改善摩擦学性能.     

含氯磷硼酸酯聚合物的摩擦性能

合成了标题聚合物,对其进行了IR表征。利用四球试验机测定其作为润滑剂的摩擦学性能。结果表明,含磷硼酸酯的最大无卡咬负荷值大于含氯硼酸酯,而且减摩抗磨效果好;含长链疏水基团的硼酸酯的最大无卡咬负荷比短链疏水基团的高,承载能力高。EDAX能谱分析表明,其抗磨性能与摩擦表面中存在硼、氯、磷活性元素有关。     

含氮杂环润滑油添加剂抗摩擦和膜化学性能

制备了N-二异辛基-2-苯并噻唑次磺酰胺(DIMB)和2-硫酮-苯并噻唑-3-甲基鄄巯基乙酸异辛酯(MBES)两种含氮杂环抗磨添加剂, 用SRV型高温摩擦磨损试验机评价它们在芋类基础油中的抗磨减摩性能, 对它们在不同条件下形成的摩擦膜进行X射线吸收精细结构光谱(XANES)分析, 用原子力显微镜(AFM)分析摩擦膜的表面形貌. 结果表明, 添加剂DIMB和MBES具有很好的抗磨性能, 但没有减摩性能. XANES分析结果表明, 添加剂MBES形成的摩擦膜完全由硫酸亚铁组成, 而添加剂DIMB形成的摩擦膜的次表面和本体主要由二硫化铁组成, 未测量到硫酸盐或硫化铁, 但摩擦膜表面部分被氧化成硫酸亚铁. AFM 测试结果表明, 与含1.5%(w)二烷基二硫代磷酸锌(ZDDP)抗磨添加剂的钢块磨损表面相比较, 分别含1.5%(w)DIMB 和1.5%(w)MBES添加剂的钢块磨损表面出现了深而宽的“犁沟”.     

Characteristics of lubrication at nanoscale in two-phase fluid system

Thin film lubrication (TFL) is a condition in which the lubricating features between two surfaces in relative motion are determined by the combination of the properties of the surfaces and the lubricant and viscosity of the lubricant. The effects imposed by couple stress on lubrication characteristics cannot be disregarded in this regime where the ordered molecules dominate the fluid field. There are different tensor measures and constitutive equations in this case other than Newtonian case. The lubrication of two-phase (solid phase and liquid phase) fluid is investigated in this paper. The existence of couple stress will enhance the lubricant viscosity and hence increase the film thickness and improve the load-carrying capability. Size-dependent effects can be seen in the lubrication with couple stress, and the thinner the lubricating film is, the more obvious the effect will be.     

Lipids and lipid mixtures in boundary layers: From hydration lubrication to osteoarthritis

The hydration layer surrounding the phosphocholine headgroups of single-component phosphatidylcholine lipids, or of lipid-mixtures, assembled at an interface greatly modifies the interfacial properties and interactions. As water molecules within the hydration layer are held tightly by the headgroup but are nonetheless very fluid on shear, the boundary lipid layers, exposing the highly hydrated headgroup arrays, can provide efficient boundary lubrication when sliding against an opposing surface, at physiologically high contact pressures. In addition, any free lipids in the surrounding liquid can heal defects which may form during sliding on the boundary phosphatidylcholine layer. Similar boundary lipid layers contribute to the lubricating, pressure-bearing, and wear-protection functions of healthy articular joints. This review presents a survey of the relationship between the molecular composition of the interfacial complex and the lubrication behavior of the lipid-based boundary layers, which could be beneficial for designing boundary lubricants for intra-articular injection for the treatment of early osteoarthritis.     

Characterization of C80 Naphthenic Acid and Its Calcium Naphthenate

A C80 naphthenic acid (tetraacid) and its calcium naphthenate have been characterized with respect to their interfacial properties at both the oil/water and the air/water interfaces as well as their thermal properties. Naphthenic acids in crude oils may give rise to different problems in oil production including naphthenate deposition and formation of stable emulsions. This may lead to severe disturbances of regularity and shut‐in in the oil production. The interfacial activity and film properties of the compounds were examined by the oscillating drop method. The calcium naphthenate film was primarily elastic and solid‐like. Measurements on the acid gave similar results, an elastic, solid‐like film was formed, but the effect was less pronounced than for the calcium naphthenate. Langmuir‐Blodgett films of the acid and its naphthenate were deposited on conducting substrates and subsequently analyzed by scanning electron microscopy, SEM. It was found that the pure acid formed crystalline structures in the interfacial film on compression. The calcium naphthenate, on the other hand, form a continuous amorphous film on the substrate.     

Reversibly Thermosecreting Organogels with Switchable Lubrication and Anti-Icing Performance

Synthetic gels with switchable interfacial properties have great potential in smart devices and controllable transport. Herein, we design an organogel by incorporating a binary liquid mixture with an upper critical solution temperature (UCST) into a polymer network, resulting in reversible modulation of lubrication and adhesion properties. As the temperature changes, the lubricating mechanism changes reversibly from boundary lubrication to hydrodynamic lubrication due to phase separation within the binary solution permeating the gel (friction coefficient 0.4–0.03). Droplets appear on the gel surface at low temperature and disappear with temperature higher than the critical phase separation temperature (T_ps) of the organogel. The organogel possesses a relatively low ice adhesive strength (less than 1 kPa). This material has potential applications in anti-icing and smart devices, and we believe that this design strategy can be expanded to other systems such as aqueous solutions and hydrogels.     

Reversibly Thermosecreting Organogels with Switchable Lubrication and Anti‐Icing Performance

Synthetic gels with switchable interfacial properties have great potential in smart devices and controllable transport. Herein, we design an organogel by incorporating a binary liquid mixture with an upper critical solution temperature (UCST) into a polymer network, resulting in reversible modulation of lubrication and adhesion properties. As the temperature changes, the lubricating mechanism changes reversibly from boundary lubrication to hydrodynamic lubrication due to phase separation within the binary solution permeating the gel (friction coefficient 0.4–0.03). Droplets appear on the gel surface at low temperature and disappear with temperature higher than the critical phase separation temperature (T_ps) of the organogel. The organogel possesses a relatively low ice adhesive strength (less than 1 kPa). This material has potential applications in anti‐icing and smart devices, and we believe that this design strategy can be expanded to other systems such as aqueous solutions and hydrogels.     

Polyzwitterionic brushes: Extreme lubrication by design

Polymers offer the advantage that they may independently combine desirable supramolecular structure with useful local monomeric properties to yield optimal performance of different tasks. Here we utilise the remarkable lubricating properties both of dense polymer brushes, and of hydration sheaths about charges via the emerging paradigm of hydration lubrication, to design a grafted-from polyzwitterionic brush system, where each of the monomers has a structure similar to the highly-hydrated phosphorylcholine headgroups of phosphatidylcholine lipids. Such polyzwitterions are grown from a macroinitiator coating the substrate (mica) surface using atom transfer radical polymerisation (ATRP) of 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) to form exceptionally robust poly(MPC) brushes. We have characterized these brush layers via X-ray reflectometry, X-ray photoelectron spectroscopy, surface forces measurements and atomic force microscopy. Such brushes, designed to optimise their lubrication properties, are indeed found to provide state of the art boundary lubrication, achieving friction coefficients as low as 0.0004 at pressures up to 75 atmospheres over a wide range of sliding velocities. Such low friction is comparable with that of articular cartilage in healthy mammalian joints, which represents nature’s benchmark for boundary lubrication in living organisms, and suggests that hydration lubrication plays a major role in reducing friction in biological systems.     

Rapid chelometric determination of lead in lubricating oils via mercaptoacetate extraction

A rapid complexometric method for the estimation of lead in lubricating oil has been developed. The lead naphthenate present in the oil is extracted with a mixture of dilute thioglycollic acid and nitric acid. The aqueous extract containing lead mercaptoacetate is titrated with EDTA at pH 5 with Xylenol Orange as indicator. The lead content can be determined within 15-20 min.     

镍催化体系合成顺式聚丁二烯的研究——Ⅶ.紫外可见光谱法探讨镍系各组分间的相互作用

环烷酸镍的汽油或甲苯溶液呈亮绿色,根据自旋允许d-d跃迁,在光谱的红和兰区有三个吸收带,其峰值分别是403、680和1170nm,络合物具有八面体构型。在Ni-Al体系中,当Al/Ni摩尔比<0.53,只发生配位体的交换反应,Al/Ni≥0.53,体系中发生还原反应,Ni(II)→Ni(I)→Ni(O)。在Ni-B体系中,只发生配位体交换反应,生成的氟-硼-镍络合物具有和环烷酸镍相类似的d-d吸收带,络合物也具有八面体构型。以上结论与磁化率法的结果一致。     

Spectroscopic analysis of the tribological behavior of a model boundary layer lubricant

Highly ordered alkanethiol self-assembled monolayers (SAMs) on gold substrates are suitable models of boundary layer lubricants and may be used in actual nanoscale device applications. Here, such monolayers were studied by spectroscopic methods as a function of tribological wear (rubbing) using a pin-on-disk microtribometer. The coefficient of friction (COF) (ratio of the frictional force to the load) was measured with the tribometer, and reflectance infrared spectra and X-ray photoelectron spectra were obtained as the monolayer film failed and the COF changed. The results show that it is possible to correlate disorder in the monolayer film with tribological failure of the film, and that continued rubbing produces a chemical change in the monolayer film. Disorder in the monolayer is distinct from the influence of wear in the underlying gold substrate. Aged SAMs, having sulfonate rather than thiol headgroups and initially less well ordered, behave differently to the well-ordered freshly prepared SAMs. Interestingly, they show a lower COF over many more cycles of exposure to the rubbing pin. The impact of the mechanism of film failure in boundary layer lubrication is discussed.     

Stepwise thickening in aqueous foam films stabilized by sodium naphthenates

During drainage of a foam film formed from an aqueous sodium naphthenate solution, a transient, local, stepwise thickening process was observed. Film stratification is related to the stepwise thinning drainage process where individual layers of material are drained from a film. The process typically involves the appearance of a sequence of small, uniformly thick spots that eventually expand to the size of the film. The appearance and growth of each spot represents a discrete decrease in the thickness of the film. The size of each decrease or step typically corresponds to the size of one or more lamella layers of the stratified film. Stepwise thinning was observed in a foam film formed from an aqueous sodium naphthenate solution, as frequently reported for a variety of systems. However, during the drainage process, a transient stepwise thickening process was also observed. Bright spots began to appear and grow, indicate a discrete increase in the thickness of a portion of the film. This local, stepwise thickening process appeared to be an alternate and temporary drainage process directly related to the expansion of the stepwise thinning spots.