One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearin...One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearing characteristics. Viscosity Index (VI) is one approach used widely in the lubricating field to assess the variation of viscosity with temperature. The VI of both mineral and synthetic base oils can be improved by the addition of polymeric viscosity modifiers (VMs). VI improvement by VMs is widely attributed to the polymer coil size expanding with increasing temperature. However, there is very little physical data supporting this generally accepted mechanism. To address this issue, intrinsic viscosity measurements and Small-Angle Neutron Scattering (SANS) have been used to study the variation of polymer coil size with changing temperature and concentration in a selection of solvents. The results will show that coil size expansion with temperature is not necessary to achieve significant elevation of viscosity index.展开更多
Viscosity index (VI) and shear stability index (SSI) are standard methods used in the lubricant industry to determine temperature-viscosity dependency and resistance to product degradation, respectively. A variety of ...Viscosity index (VI) and shear stability index (SSI) are standard methods used in the lubricant industry to determine temperature-viscosity dependency and resistance to product degradation, respectively. A variety of oil-soluble polymers, including poly(alkyl methacrylates) (PAMAs) are routinely used to control these properties in fully-formulated liquid lubricants. In this report, we use reversible addition-fragmentation chain transfer (RAFT) polymerization to precisely target identical degrees of polymerization in a family of PAMAs with varying lauryl, hexyl, butyl, ethyl, and methyl groups. Then, expanding on previous methodology reported in the literature, we establish structure property relationships for these PAMAs, specifically looking at how intrinsic viscosity [η] and Martin interaction parameters K<sub>M</sub> relate to VI and SSI characteristics. While the intrinsic viscosity [η] is associated with the volume of macromolecules at infinite dilution, the parameter K<sub>M</sub> reflects the hydrodynamic interactions of polymer chains at actual polymer concentrations in lubricating oils. In this paper, we show that the dependence of VI on the non-dimensional concentration c/c* (or c[η]) can be presented in a form of master curve with shift factors proportional to K<sub>M</sub> that decreases with increasing size of alkyl groups. This finding implies that even in the dilute regime, the coil-expansion theory used to explain the effect of macromolecules on VI should be complemented with the idea of hydrodynamic interactions between polymer molecules that can be controlled by the choice of alkyl chains in the family of PAMAs.展开更多
Durability has always been the primary function of an engine oil.This continues to be the case,but fuel economy improvement has risen in importance as a feature of a lubricant.This is most easily achieved by lower vis...Durability has always been the primary function of an engine oil.This continues to be the case,but fuel economy improvement has risen in importance as a feature of a lubricant.This is most easily achieved by lower viscosity lubricants,which could endanger the durability of the engine if not properly formulated.Additionally,fuel economy from the lubricant is also considered over the course of a drain interval and the cost optimal point of servicing the oil explored,independent of other durability concerns.Durability is even more critical when the operating severities of the Chinese market are taken into account.Data are presented which demonstrate the differences in severity and the implications this will have on the lubricant,demonstrating the need for high quality lubricants that will protect Chinese vehicles in operation and,in addition,achieve some level of fuel economy improvement.展开更多
This paper describes a battery of tests, and related results, that were performed under normal and severe conditions designed to demonstrate that hydraulic fluids formulated with Lubrizol’s high quality anti-wear hyd...This paper describes a battery of tests, and related results, that were performed under normal and severe conditions designed to demonstrate that hydraulic fluids formulated with Lubrizol’s high quality anti-wear hydraulic fluid technology can stand up to today’s increasing demands for longer life and provide excellent performance under higher operating temperatures and pressures.展开更多
This paper described a new type of multifunctional polymer Noverite^(TM) AD810's calcium ion chelating performance, tinted glass soaking test and its application in containing chlorine or enzyme automatic dishwash...This paper described a new type of multifunctional polymer Noverite^(TM) AD810's calcium ion chelating performance, tinted glass soaking test and its application in containing chlorine or enzyme automatic dishwashing detergent gel and powder. Results showed Noverite^(TM) AD810 has good performance in the final formulation on chelation, anti-filming, and anti-spotting, as well as to prevent the growth of scale crystals.展开更多
A kinetics problem for a degrading polymer additive dissolved in a base stock is studied.The polymer degradation may be caused by the combination of such lubricant flow parameters aspressure, elongational strain rate,...A kinetics problem for a degrading polymer additive dissolved in a base stock is studied.The polymer degradation may be caused by the combination of such lubricant flow parameters aspressure, elongational strain rate, and temperature as well as lubricant viscosity and the polymercharacteristics (dissociation energy, bead radius, bond length, etc.). A fundamental approach tothe problem of modeling mechanically induced polymer degradation is proposed. The polymerdegradation is modeled on the basis of a kinetic equation for the density of the statistical distribu-tion of polymer molecules as a function of their molecular weight. The integrodifferential kineticequation for polymer degradation is solved numerically. The effects of pressure, elongational strainrate, temperature, and lubricant viscosity on the process of lubricant degradation are considered.The increase of pressure promotes fast degradation while the increase of temperature delaysdegradation. A comparison of a numerically calculated molecular weight distribution with an ex-perimental one obtained in bench tests showed that they are in excellent agreement with eachother.展开更多
文摘One of the requirements of engine lubricating oil is that it must have a low enough viscosity at low temperatures to assist in cold starting and a high enough viscosity at high temperatures to maintain its load-bearing characteristics. Viscosity Index (VI) is one approach used widely in the lubricating field to assess the variation of viscosity with temperature. The VI of both mineral and synthetic base oils can be improved by the addition of polymeric viscosity modifiers (VMs). VI improvement by VMs is widely attributed to the polymer coil size expanding with increasing temperature. However, there is very little physical data supporting this generally accepted mechanism. To address this issue, intrinsic viscosity measurements and Small-Angle Neutron Scattering (SANS) have been used to study the variation of polymer coil size with changing temperature and concentration in a selection of solvents. The results will show that coil size expansion with temperature is not necessary to achieve significant elevation of viscosity index.
文摘Viscosity index (VI) and shear stability index (SSI) are standard methods used in the lubricant industry to determine temperature-viscosity dependency and resistance to product degradation, respectively. A variety of oil-soluble polymers, including poly(alkyl methacrylates) (PAMAs) are routinely used to control these properties in fully-formulated liquid lubricants. In this report, we use reversible addition-fragmentation chain transfer (RAFT) polymerization to precisely target identical degrees of polymerization in a family of PAMAs with varying lauryl, hexyl, butyl, ethyl, and methyl groups. Then, expanding on previous methodology reported in the literature, we establish structure property relationships for these PAMAs, specifically looking at how intrinsic viscosity [η] and Martin interaction parameters K<sub>M</sub> relate to VI and SSI characteristics. While the intrinsic viscosity [η] is associated with the volume of macromolecules at infinite dilution, the parameter K<sub>M</sub> reflects the hydrodynamic interactions of polymer chains at actual polymer concentrations in lubricating oils. In this paper, we show that the dependence of VI on the non-dimensional concentration c/c* (or c[η]) can be presented in a form of master curve with shift factors proportional to K<sub>M</sub> that decreases with increasing size of alkyl groups. This finding implies that even in the dilute regime, the coil-expansion theory used to explain the effect of macromolecules on VI should be complemented with the idea of hydrodynamic interactions between polymer molecules that can be controlled by the choice of alkyl chains in the family of PAMAs.
文摘Durability has always been the primary function of an engine oil.This continues to be the case,but fuel economy improvement has risen in importance as a feature of a lubricant.This is most easily achieved by lower viscosity lubricants,which could endanger the durability of the engine if not properly formulated.Additionally,fuel economy from the lubricant is also considered over the course of a drain interval and the cost optimal point of servicing the oil explored,independent of other durability concerns.Durability is even more critical when the operating severities of the Chinese market are taken into account.Data are presented which demonstrate the differences in severity and the implications this will have on the lubricant,demonstrating the need for high quality lubricants that will protect Chinese vehicles in operation and,in addition,achieve some level of fuel economy improvement.
文摘This paper describes a battery of tests, and related results, that were performed under normal and severe conditions designed to demonstrate that hydraulic fluids formulated with Lubrizol’s high quality anti-wear hydraulic fluid technology can stand up to today’s increasing demands for longer life and provide excellent performance under higher operating temperatures and pressures.
文摘This paper described a new type of multifunctional polymer Noverite^(TM) AD810's calcium ion chelating performance, tinted glass soaking test and its application in containing chlorine or enzyme automatic dishwashing detergent gel and powder. Results showed Noverite^(TM) AD810 has good performance in the final formulation on chelation, anti-filming, and anti-spotting, as well as to prevent the growth of scale crystals.
文摘A kinetics problem for a degrading polymer additive dissolved in a base stock is studied.The polymer degradation may be caused by the combination of such lubricant flow parameters aspressure, elongational strain rate, and temperature as well as lubricant viscosity and the polymercharacteristics (dissociation energy, bead radius, bond length, etc.). A fundamental approach tothe problem of modeling mechanically induced polymer degradation is proposed. The polymerdegradation is modeled on the basis of a kinetic equation for the density of the statistical distribu-tion of polymer molecules as a function of their molecular weight. The integrodifferential kineticequation for polymer degradation is solved numerically. The effects of pressure, elongational strainrate, temperature, and lubricant viscosity on the process of lubricant degradation are considered.The increase of pressure promotes fast degradation while the increase of temperature delaysdegradation. A comparison of a numerically calculated molecular weight distribution with an ex-perimental one obtained in bench tests showed that they are in excellent agreement with eachother.
