The Viscosity of Polyalphaolefins Mixtures at High Pressure and Stress

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Scott Bair ◽  
Samuel Flores-Torres
Keyword(s):  
High Pressure ◽  
Shear Stress ◽  
Film Thickness ◽  
Shear Viscosity ◽  
Mixing Rule ◽  
Base Oils ◽  
Film Forming ◽  
Low Shear Viscosity ◽  
Temperature And Pressure ◽  
Low Shear

Understanding the pressure and shear dependence of viscosity is essential to an understanding of the mechanisms of film forming and friction in concentrated contacts. The blending of different molecular mass polyalphaolefins (PAOs) may permit the formulator to arrive at a desired combination of film thickness and friction. The viscosities of PAO base oils and their blends were measured versus temperature, pressure, and shear stress to 1 GPa in pressure. The Grunberg–Nissan mixing rule, with effective mole fractions, provides an excellent mixing rule for the temperature and pressure-dependent low-shear viscosity. This work provides the first look at a possible mixing rule for the non-Newtonian response of mixtures of base oils.

Low shear viscosity of polypropylene melts

1963 ◽  
Vol 1 (7) ◽  
pp. 381-384 ◽  
Author(s):  
D. Poller ◽  
A. M. Kotliar ◽  
R. L. Kruse
Keyword(s):  
Shear Viscosity ◽  
Low Shear Viscosity ◽  
Low Shear

Dispersion and Rheological Properties of Alumina Freeze Casting Slurries Containing Nanoparticle/Whisker SiC

2007 ◽  
Vol 280-283 ◽  
pp. 1035-1038 ◽  
Author(s):  
Tae Young Yang ◽  
Young Min Park ◽  
Gun Dae Lee ◽  
Seog Young Yoon ◽  
Ron Stevens ◽  
...  
Keyword(s):  
Shear Rate ◽  
Shear Viscosity ◽  
Pure Alumina ◽  
Rheological Measurements ◽  
Continuous Shear ◽  
Suspension Viscosity ◽  
Low Shear Viscosity ◽  
Opposite Manner ◽  
High Structure ◽  
Low Shear

The sedimentation density significantly decreased after addition of dispersant; the effect was more pronounced with pure alumina, as compared with SiC-containing slurry. With further addition of surfactant, the sedimentation density increased somewhat, but decreased with binderadditions. The suspension viscosity generally behaved in an opposite manner to the sedimentation density, i.e., low sedimentation density gave high low-shear viscosity, indicative of high structure formation in the suspended particles. Shear rate rheological measurements showed continuous shear thinning behavior.

Effects of polymers concentration on EHL film-forming in point contacts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liangwei Qiu ◽  
Xiaoyang Chen ◽  
Fakai Dong
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Point Contact ◽  
High Concentration ◽  
Content Type ◽  
Base Oils ◽  
Low Viscosity ◽  
Lubricant Oil ◽  
Pure Rolling ◽  
Film Forming

Purpose This paper aims to experimentally investigate the film-forming capability of base oils containing poly-methacrylate (PMA) and poly-isobutene (PIB), in a point contact under pure rolling. Design/methodology/approach By using the relative light intensity method, the film thickness is calculated from the interferometer images which are captured by multiple-contact optical elastohydrodynamic lubricated test rig. Findings The test results reveal that polymers, both PMA and PIB, have a significant contribution to the film-forming capability of base oils and the film thickness increases with concentration. The forming-film capabilities for PMA and PIB in base oils are similar at low concentration, while PIB gives a higher film thickness than PMA at high concentration. Shear-thinning phenomenon are observed in all polymer-based oils. Originality/value The polymer usually as an additive is added into the low viscosity base oils to improve the properties of lubricant oil. This paper reports the lubricated properties of PMA and PIB with different concentrations in base oils and to evaluate their functional mechanism in a point contact. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0263/

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