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An ‘in lubro’ study of viscosity index improvers in end contacts
Author(s) -
Wardle R. W. M.,
Coy R. C.,
Cann P. M.,
Spikes H. A.
Publication year - 1990
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.3010030104
Subject(s) - viscosity , viscosity index , materials science , interferometry , polymer , reflectivity , composite material , degradation (telecommunications) , shear viscosity , shear (geology) , chemical engineering , forensic engineering , optics , computer science , engineering , telecommunications , physics , scanning electron microscope , base oil
Polymeric viscosity index (VI) improver solutions in oils suffer from both temporary and permanent viscosity losses in high shear hydrodynamic and elastohydrodynamic (EHD) contacts. In some cases in EHD contacts, these losses can be so severe that the additive makes negligible contribution to oil film thickness. This paper describes the use of a combination of optical interferometry and FTIR micro‐reflectance spectroscopy to measure the effectiveness, and to observe directly the behaviour, of conventional VI improver solutions within rolling and sliding EHD contacts. The study shows the extent to which polymers enter EHD contacts and charts the degradation that they suffer therein.