Influence of Polyalkylmethacrylate VII on Boundary Film Formation,Friction,Wear and Efficiency of Lubricants

1 Influence of PAMAon Boundary Fil mFormation and Friction1.1 Experi mental methodsUltra-thin optical interferometry has been used tostudy thinlubricating fil ms for more than a decade and theexperi mental details of this technique have been reportedpreviously[1].The principle of the test setup is shown inFigure1.A polished steel ball is loaded and rolled againstthe flat surface of a glass disc that is coated with a thinsemi-reflecting chromiumlayer and a silica spacer of about500nmthickne…     

高吸水性树脂PAMA的超声制备与性能研究

超声辐射下,以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为原料,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,合成AM/ AMPS(PAMA)共聚高吸水性树脂.结果表明:单体中AM的质量分数25%、反应体系pH值为2.0、反应温度为45 ℃和交联剂的质量分数为0.01%时,PAMA共聚高吸水性树脂的吸...     

Performance and Selection of Pour Point Depressants

1 IntroductionParaffinic mineral oil base stocks contain waxy hydro-carbons that come out of solution when temperature de-creases.The lower the molecular weight of the paraffinand the higher its level of branching,thelower the precipi-tation temperature.Initially,tiny crystals are for medwhich diffract light making the solution hazy to the nakedeye.The temperature at which this occurs is called thecloud point.When temperature is further lowered,addi-tional wax precipitates,the crystals grow i…     

Telechelic polymers by living and controlled/living polymerization methods

Telechelic polymers, defined as macromolecules that contain two reactive end groups, are used as cross-linkers, chain extenders, and important building blocks for various macromolecular structures, including block and graft copolymers, star, hyperbranched or dendritic polymers. This review article describes the general techniques for the preparation of telechelic polymers by living and controlled/living polymerization methods; namely atom transfer radical polymerization, nitroxide mediated radical polymerization, reversible addition-fragmentation chain transfer polymerization, iniferters, iodine transfer polymerization, cobalt mediated radical polymerization, organotellurium-, organostibine-, organobismuthine-mediated living radical polymerization, living anionic polymerization, living cationic polymerization, and ring opening metathesis polymerization. The efficient click reactions for the synthesis of telechelic polymers are also presented.     

Hollow polymeric nanostructures—Synthesis, morphology and function

The development of reliable synthetic routes to polymeric nanostructures of well-defined composition, morphology and function is of scientific importance and technological interest. The generation of functional hollow polymeric nanostructures, hollow nanospheres and nanotubes in particular, can be achieved through direct and template-directed synthesis, core-shell precursors, and self-assembly of copolymers and polymer conjugates, as well as from dendrimers. The ability to prepare precursor macromolecules of well-defined structure and architecture has been substantially enhanced by recent advances in controlled radical polymerizations. The application and potential application of the hollow polymeric nanospheres and nanotubes as nanoreactors, and in diagnostics, encapsulation, controlled release, and other stimuli-responsive systems are also described.     

Influence of Polyalkylmethacrylate VIIs on Boundary Film Formation,Friction,Wear and Efficiency of Lubricants

Polyalkylmethacrylates (PAMAs) are well-known as viscosity index improvers and dispersant boosters. This paper shows that PAMAs are able to adsorb from oil solution on to metal surfaces, to produce thick, viscous boundary films.These films enhance lubricant film formation in slow speed and high temperature conditions and thus produce a significant reduction of friction. A systematic study of this phenomenon has made use of the highly flexible nature of PAMA chemistry. A range of dispersant and non-dispersant polymethacrylates has been synthesized. The influence of different functionalities, molecular weights and architectures on both boundary film formation and friction has been explored using optical interferometry and friction-speed charting. From the results, guidelines have been developed for designing PAMAs having optimal boundary lubricating properties.Through their ability to form boundary films PAMAs can significantly contribute to reduce wear in engine, gear and hydraulic lubrication. As a consequence of their viscometric and tribological performance PAMAs can furthermore improve fuel and energy efficiency in different, namely engine and hydraulic applications.Extensive work is currently conducted in the lubricant industry to develop engine oils with lower sulfur, phosphorus and metal content (low SAPS) and to optimize their frictional properties through the use of friction modifiers or synthetic base stocks. We have investigated the contribution of PAMA viscosity index improvers and boosters to improve fuel economy and to reduce wear levels. This paper reports our efforts to develop a new range of PAMAs that have been optimized in terms of composition, architecture, molecular weight and functionality and which can be used in low viscosity, low SAPS formulations to help meet the stringent requirements of modern engine oils.