The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils

Viscosity index improvers are polymeric additives that are commonly used to control the viscometrics of lubricants. Nevertheless, there have been few studies on the molecular size of these additives, which is the origin of their viscosity-increasing effects. We herein show the fundamental difference...

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Autores principales:	Kazushi Tamura, Taeko Nakano
Formato:	article
Lenguaje:	EN
Publicado:	Japanese Society of Tribologists 2019
Materias:	viscosity modifier intrinsic viscosity olefin copolymer polyalkylmethacrylate polymethacrylate Physics QC1-999 Engineering (General). Civil engineering (General) TA1-2040 Mechanical engineering and machinery TJ1-1570 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/b5ffbf8463704f4ea417f729d72f008f
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spelling	oai:doaj.org-article:b5ffbf8463704f4ea417f729d72f008f2021-11-05T09:17:37ZThe Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils1881-219810.2474/trol.14.188https://doaj.org/article/b5ffbf8463704f4ea417f729d72f008f2019-10-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/trol/14/4/14_188/_pdf/-char/enhttps://doaj.org/toc/1881-2198Viscosity index improvers are polymeric additives that are commonly used to control the viscometrics of lubricants. Nevertheless, there have been few studies on the molecular size of these additives, which is the origin of their viscosity-increasing effects. We herein show the fundamental differences of the topological features of two types of viscosity index improver molecules: olefin copolymers and polyalkylmethacrylates. The hydrodynamic radii of these viscosity index improvers were estimated from their intrinsic viscosity with varying molecular weights. The measured relationships between the hydrodynamic radii and molecular weight were compared to the theories of polymer chain mechanics. The behaviors of olefin copolymers likely correspond to the classical theory of polymer chains with excluded-volume effects. Polyalkylmethacrylates showed features of both an ideal chain and an excluded-volume chain, depending on the temperature, molecular weight, and side chain heterogeneity. The hydrodynamic radii of olefin copolymers decreased with increasing temperature independently of their molecular weight. Meanwhile, the hydrodynamic radii of polyalkylmethacrylates increased with increasing temperature in a molecular weight-dependent manner. The coil expansion of polyalkylmethacrylates might result from the extension of an effective bond angle and transition from an ideal to an excluded-volume chain.Kazushi TamuraTaeko NakanoJapanese Society of Tribologistsarticleviscosity modifierintrinsic viscosityolefin copolymerpolyalkylmethacrylatepolymethacrylatePhysicsQC1-999Engineering (General). Civil engineering (General)TA1-2040Mechanical engineering and machineryTJ1-1570ChemistryQD1-999ENTribology Online, Vol 14, Iss 4, Pp 188-193 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	viscosity modifier intrinsic viscosity olefin copolymer polyalkylmethacrylate polymethacrylate Physics QC1-999 Engineering (General). Civil engineering (General) TA1-2040 Mechanical engineering and machinery TJ1-1570 Chemistry QD1-999
spellingShingle	viscosity modifier intrinsic viscosity olefin copolymer polyalkylmethacrylate polymethacrylate Physics QC1-999 Engineering (General). Civil engineering (General) TA1-2040 Mechanical engineering and machinery TJ1-1570 Chemistry QD1-999 Kazushi Tamura Taeko Nakano The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils
description	Viscosity index improvers are polymeric additives that are commonly used to control the viscometrics of lubricants. Nevertheless, there have been few studies on the molecular size of these additives, which is the origin of their viscosity-increasing effects. We herein show the fundamental differences of the topological features of two types of viscosity index improver molecules: olefin copolymers and polyalkylmethacrylates. The hydrodynamic radii of these viscosity index improvers were estimated from their intrinsic viscosity with varying molecular weights. The measured relationships between the hydrodynamic radii and molecular weight were compared to the theories of polymer chain mechanics. The behaviors of olefin copolymers likely correspond to the classical theory of polymer chains with excluded-volume effects. Polyalkylmethacrylates showed features of both an ideal chain and an excluded-volume chain, depending on the temperature, molecular weight, and side chain heterogeneity. The hydrodynamic radii of olefin copolymers decreased with increasing temperature independently of their molecular weight. Meanwhile, the hydrodynamic radii of polyalkylmethacrylates increased with increasing temperature in a molecular weight-dependent manner. The coil expansion of polyalkylmethacrylates might result from the extension of an effective bond angle and transition from an ideal to an excluded-volume chain.
format	article
author	Kazushi Tamura Taeko Nakano
author_facet	Kazushi Tamura Taeko Nakano
author_sort	Kazushi Tamura
title	The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils
title_short	The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils
title_full	The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils
title_fullStr	The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils
title_full_unstemmed	The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils
title_sort	hydrodynamic radii of viscosity index improvers for lubricant oils
publisher	Japanese Society of Tribologists
publishDate	2019
url	https://doaj.org/article/b5ffbf8463704f4ea417f729d72f008f
work_keys_str_mv	AT kazushitamura thehydrodynamicradiiofviscosityindeximproversforlubricantoils AT taekonakano thehydrodynamicradiiofviscosityindeximproversforlubricantoils AT kazushitamura hydrodynamicradiiofviscosityindeximproversforlubricantoils AT taekonakano hydrodynamicradiiofviscosityindeximproversforlubricantoils
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The Hydrodynamic Radii of Viscosity Index Improvers for Lubricant Oils

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