Tribological characterization of green lubricating greases formulated with castor oil and different biogenic thickener agents: a comparative experimental study

Tribological characterization of green lubricating greases formulated with castor oil and... Purpose – The aim of this paper is to characterize some selected formulations based on castor oil and a variety of biogenic thickeners from a tribological point of view and compare them with some traditional lithium greases. Design/methodology/approach – The evolution of the friction coefficient in several tribological tests performed using several ball‐on‐disc configurations and coupling materials was monitored for the different oleogels proposed as biodegradable lubricating greases. Both a rotational ball‐on‐disc classical tribometer designed at MuT laboratory and a nanotribometer were used in rotational and oscillatory modes. Findings – Generally, the use of castor oil‐based formulations potentially applicable as biodegradable lubricating greases provides similar or lower values of the friction coefficient than traditional lithium greases, depending on the nature of thickener agent employed and tribological contact. In all cases, biodegradable formulations provide significantly lower values of the friction coefficient in tribological tests performed in the oscillatory mode. Weak oleogels like those thickened with glyceryl and sorbitan monostearates or acylated chitosan, provide the lowest values of the friction coefficient in every type of configuration or frictional test analysed. Biogrease formulations containing cellulose or chitin derivatives as thickener agents generally yield higher values of the friction coefficient, which may be comparable to those obtained with the reference lithium greases depending on the thickener and tribological configuration. In frictional tests performed in the rotational mode, the inclusion of ethyl cellulose in the formulation yields high values of the friction coefficient, which was attributed to the castor oil viscosity modification exerted by this additive. Wear results depend on the balance between the frictional behaviour, especially in the initial transient regime, and oleogel mechanical stability. Practical implications – This investigation proposes different new alternatives to replace the traditional thickener agent in lubricating greases with others based on renewable resources in order to obtain a completely biodegradable formulation for different industrial applications. Originality/value – This paper provides a resource of new practical friction coefficient data as well as a comparative analysis of the tribological response of these new formulations based on biogenic thickeners and other traditional lithium greases. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Industrial Lubrication and Tribology Emerald Publishing

Tribological characterization of green lubricating greases formulated with castor oil and different biogenic thickener agents: a comparative experimental study

Loading next page...
 
/lp/emerald-publishing/tribological-characterization-of-green-lubricating-greases-formulated-g5lxESUDSs
Publisher
Emerald Publishing
Copyright
Copyright © 2011 Emerald Group Publishing Limited. All rights reserved.
ISSN
0036-8792
DOI
10.1108/00368791111169034
Publisher site
See Article on Publisher Site

Abstract

Purpose – The aim of this paper is to characterize some selected formulations based on castor oil and a variety of biogenic thickeners from a tribological point of view and compare them with some traditional lithium greases. Design/methodology/approach – The evolution of the friction coefficient in several tribological tests performed using several ball‐on‐disc configurations and coupling materials was monitored for the different oleogels proposed as biodegradable lubricating greases. Both a rotational ball‐on‐disc classical tribometer designed at MuT laboratory and a nanotribometer were used in rotational and oscillatory modes. Findings – Generally, the use of castor oil‐based formulations potentially applicable as biodegradable lubricating greases provides similar or lower values of the friction coefficient than traditional lithium greases, depending on the nature of thickener agent employed and tribological contact. In all cases, biodegradable formulations provide significantly lower values of the friction coefficient in tribological tests performed in the oscillatory mode. Weak oleogels like those thickened with glyceryl and sorbitan monostearates or acylated chitosan, provide the lowest values of the friction coefficient in every type of configuration or frictional test analysed. Biogrease formulations containing cellulose or chitin derivatives as thickener agents generally yield higher values of the friction coefficient, which may be comparable to those obtained with the reference lithium greases depending on the thickener and tribological configuration. In frictional tests performed in the rotational mode, the inclusion of ethyl cellulose in the formulation yields high values of the friction coefficient, which was attributed to the castor oil viscosity modification exerted by this additive. Wear results depend on the balance between the frictional behaviour, especially in the initial transient regime, and oleogel mechanical stability. Practical implications – This investigation proposes different new alternatives to replace the traditional thickener agent in lubricating greases with others based on renewable resources in order to obtain a completely biodegradable formulation for different industrial applications. Originality/value – This paper provides a resource of new practical friction coefficient data as well as a comparative analysis of the tribological response of these new formulations based on biogenic thickeners and other traditional lithium greases.

Journal

Industrial Lubrication and TribologyEmerald Publishing

Published: Sep 27, 2011

Keywords: Biopolymers; Biodegradable lubricant; Lubricating greases; Tribology; Friction

References

  • Tribological studies of thermally and chemically modified vegetable oils for use as environmentally friendly lubricants
    Adhvaryu, A.; Erhan, S.Z.; Perez, J.M.
  • Lubricants and the environment
    Bartz, W.J.
  • European development of lubricants derived from renewable resources
    Lea, C.W.
  • Rheology of colloidal suspensions: case of lubricating greases
    Mas, R.; Magnin, A.
  • Use of chitin, chitosan and acylated derivatives as thickener agents of vegetable oils for bio‐lubricant applications
    Sánchez, R.; Stringari, G.B.; Franco, J.M.; Valencia, C.; Gallegos, C.
  • Lubricants and functional fluids from renewable sources
    Wilson, B.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off