Mechanical and tribological properties of acrylonitrile–butadiene rubber filled with graphite and carbon black

Published Date
Materials & Design
August 2012, Vol.39:450–457, doi:10.1016/j.matdes.2012.02.051

• Author 

• Lei Lei Wang
• Li Qun Zhang
• Ming Tian ^,,

• The Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, China
• The Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China

Received 29 December 2011. Accepted 24 February 2012. Available online 3 March 2012. 

Abstract

In this work, acrylonitrile–butadiene rubber (NBR)/expanded graphite (EG)/carbon black (CB) micro- and nanocomposites were prepared by two different methods, and the resulting mechanical and tribological properties were compared with those of NBR/CB composites. Meanwhile, the effects of graphite dispersion and loading content, as well as the applied load and sliding velocity on the tribological behavior of the above composites under dry friction condition were also evaluated. The worn surfaces were analyzed by scanning electron microscopy (SEM) to disclose wear mechanism. As expected, the better the dispersion of graphite, the more remarkable enhancement on tensile and dynamic mechanical properties, and the greater reduction in the coefficient of friction (COF) and specific wear rate (W_s). It was found that a small amount of EG could effectively decrease COF and W_s of NBR/CB composites because of the formation of graphite lubricant films. The COF and W_s of NBR/CB/EG composites show a decreasing trend with a rise in applied load and sliding velocity. NBR/CB/EG nanocomposite always shows a stable wearing process with relatively low COF and W_s. It is thought that well-dispersed graphite nano-sheets were beneficial to the formation of a fine and durable lubricant film.

Highlights

► Graphite/carbon black/rubber micro- and nano-composites were prepared. ► Nanocomposites showed better mechanical properties and wear resistance. ► The effect of load and sliding speed on friction and wear is significant. ► Graphite lubricant film can reduce friction coefficient and wear rate.

Keywords

A. Elastomers and rubber

E. Mechanical properties

E. Wear

---

 Table 1

Table 1.

Fig. 1.

 Table 2

Table 2.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

 Table 3

Table 3.

Fig. 8.

Fig. 9.

• ⁎ 
  Corresponding author. Address: P.O. Box 57, Beijing University of Chemical Technology, No. 15 Beisanhuan East Road, Chaoyang District, Beijing 100029, China. Tel.: +86 10 6443 4860; fax: +86 10 6443 3964.

For further details log on website :
http://www.sciencedirect.com/science/article/pii/S0261306912001306

The influence of cyclic loading conditions on the viscoelastic properties of filled rubber

Published Date
Mechanics of Materials
January 2013, Vol.56:84–94, doi:10.1016/j.mechmat.2012.10.001

• Author 

• P. Garnier ^a,b,c
• J.-B. Le Cam ^b,,
• M. Grédiac ^a

• aUniversité Blaise Pascal-Institut Français de Mécanique Avancée, Laboratoire de Mécanique et Ingénieries, BP 265, 63175 Clermont-Ferrand, France
• bUniversité de Rennes 1, LARMAUR, ERL CNRS 6274, Campus de Beaulieu, 35042 Rennes Cedex, France
• cPCM, 1 Rue René Moineau, F-49000 Champtocé sur Loire, France

Received 14 February 2012. Revised 27 September 2012. Available online 11 October 2012. 

Abstract

This study deals with the effect of cyclic loading on the viscoelastic properties of filled nitrile rubbers. Classic strain amplitude sweeps were first carried out at two different temperatures (ambient and 80 °C) on both filled and unfilled nitrile rubber specimens in order to observe the influence of the fillers, temperature and loading conditions on the Payne effect. Some specimens were then subjected to a high number of cycles to study the variations in the viscoelastic properties and the sensitivity of the Payne effect to cyclic loading tests at several given strain amplitudes. It appears that the viscoelastic properties of rubber significantly evolve during the cyclic tests, which raises the question of the concept of cyclic stabilized behaviour.

Highlights

► The viscoelastic properties clearly evolve during the cyclic loading tests. ► After the stress softening step,   is greater than its initial value, apart from the highest DSA. ► At 80 °C,   slowly increases after a short softening phase, due to vulcanization.

Keywords

Payne effect

Viscoelasticity

Filler effects

Temperature effects

Nitrile rubber

---

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

Fig. 9.

Fig. 10.

Fig. 11.

Fig. 12.

Fig. 13.

Fig. 14.

• ⁎ 
  Corresponding author.
  
  

For further details log on website :
http://www.sciencedirect.com/science/article/pii/S0167663612001688

The influences of deformation state and experimental conditions on inelastic behaviour of an extruded thermoplastic polyurethane elastomer

Published Date
Materials & Design
August 2013, Vol.49:974–980, doi:10.1016/j.matdes.2013.02.055

• Author 

• Luis Bartolomé ^a,,
• Jon Aurrekoetxea ^a
• Mikel A. Urchegui ^b
• Wilson Tato ^a

• aMechanical and Manufacturing Department, Mondragon Unibertsitatea, Loramendi 4, 20500 Mondragón, Spain
• bMechanical Engineering, Orona eic S. Coop., Pol. Ind. Lastaola s/n, 20120 Hernani, Spain

Received 11 December 2012. Accepted 20 February 2013. Available online 1 March 2013. 

Abstract

Thermoplastic polyurethane elastomers under cyclic loading–unloading conditions exhibit inelastic effects, mainly stress softening, hysteresis loss and residual strain. In order to discuss the sensitivity of these effects to deformation state (uniaxial tension and pure shear) and to work conditions (maximum strain, strain-rate and stretching direction), this study is concerned with inelastic effects of an extruded thermoplastic polyurethane elastomer when is subjected to loading–unloading cycles. Based on the behaviour of inelastic effects under both tensile conditions, the present work shows that stress softening and residual strain are sensitive to deformation state only when the maximum strain reached causes permanent set. Furthermore, the hysteresis loss shows an independent behaviour depending on maximum strain. Finally, the behaviour of the hysteresis loss and the residual strain is isotropic for the extruded thermoplastic polyurethane elastomer.

Highlights

► We analyze behaviour of inelastic effects of a thermoplastic polyurethane elastomer. ► Stress softening, hysteresis loss and residual strain are the inelastic effects. ► Stress softening and residual strain are influenced by the maximum strain reached. ► Hysteresis loss exhibits a independent behaviour with maximum strain. ► The behaviour of all inelastic effects is isotropic.

Keywords

Thermoplastic polyurethane elastomer

Inelasticity

Stress softening

Hysteresis loss

Residual strain

---

Fig. 1.

Fig. 2.

 Table 1

Table 1.

Fig. 3.

 Table 2

Table 2.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

Fig. 9.

Fig. 10.

Fig. 11.

Fig. 12.

Fig. 13.

Fig. 14.

• ⁎ 
  Corresponding author. Tel.: +34 943 73 96 92; fax: +34 943 71 19 12.
  
  

For further details log on website :
http://www.sciencedirect.com/science/article/pii/S0261306913001660