Article citationsMore>>

Melnichenko, Y.B., Kiran, E., Heath, K., Salaniwal, S., Cochran, H.D., Stamm, M., Hook, W.A.V. and Wignall, G.D. (1999) SANS Studies of Polymers in Organic Solvents and Supercritical Fluids in the Poor, Theta and Good Solvent Domains. In: Cebe, P., Ed., Scattering from Polymers, ACS Symposium Series, Washington, 317-327.

has been cited by the following article:

• TITLE: How Polymers Behave as Viscosity Index Improvers in Lubricating Oils

  AUTHORS: Michael J. Covitch, Kieran J. Trickett

  KEYWORDS: Viscosity Index Improver, Viscosity Modifier, Polymer, Small-Angle Neutron Scattering, Rheology

  JOURNAL NAME: Advances in Chemical Engineering and Science, Vol.5 No.2, March 24, 2015

  ABSTRACT: 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.