Effects of Particle-Induced Crystallization on Tribological Behavior of Polymer Nanocomposites

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
David Huitink ◽  
Tahira Zarrin ◽  
Matthew Sanders ◽  
Subrata Kundu ◽  
Hong Liang

Similar to conventional engineering fabrication processes, tribological performance of drugs and pills in pharmaceutical manufacturing plays an important role in quality and product yields. In the present research, we investigate the effects of crystal structures of workpiece materials on their tribological performance in conditions typical of pharmaceutical manufacturing processes. Sorbitol composites containing gold nanoparticles were evaluated for material properties and tribological performance. It was found that the control exhibited nonordered gamma forms of sorbitol, while the samples containing rod nanoparticles showed a collection of tiny needlelike crystals of gamma phase. Spherical nanoparticles precipitated beta and alpha phases of sorbitol, which were not seen in the other samples. These variations in the crystal structure resulted in an unusual wear behavior, leading to high friction and softness in the case of the nanocomposites. The nanoparticles were found to influence the crystal structure of the sorbitol matrix, resulting in mechanical and tribological behaviors.

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Carlton J. Reeves ◽  
Arpith Siddaiah ◽  
Pradeep L. Menezes

The sustainability of biolubricants as green alternatives for industrial and machinery lubrication is questionable due to their unreliable oxidative stability, high pour point, and easy accumulation of contaminants that affect their tribological performance. Bio-based ionic liquid (IL) lubricants, which are environmentally friendly liquid state salts, have overcome these concerns related to conventional biolubricants. The present study investigates the effect of varying cation–anion moieties in ILs to understand their tribological performance and industrial viability. The industrial viability was analyzed by scaling their friction and wear behaviors against conventional biolubricants, and petroleum-based oils. The study investigated both bio- and nonbio-based ILs. Among the ILs examined, P666,14Saccharinate, P666,14Salicyate, and P666,14Benzoate were found to have superior tribological properties. The presence of large alkyl cation chain length and large aromatic anion ring size in ILs can effectively reduce friction and wear. This study details the mechanism by which the structural combinations of anion and cation in ILs define the tribological behavior of the bulk IL. Additionally, this study also highlights the environmentally benign nature of IL lubricants for possible industrial applications.


2008 ◽  
Vol 8 (9) ◽  
pp. 4869-4872 ◽  
Author(s):  
Sung-Rok Ha ◽  
Kyong-Yop Rhee ◽  
Hyunho Shin

Numerous studies have investigated the material properties of clay/polymer nanocomposites, such as their fracture toughness, elastic modulus, and hardness. However, only a few researchers have studied the tribological properties of clay/polymer nanocomposites. This study investigated the effect of the montmorillonite (MMT) concentration on the tribological behavior of MMT/epoxy nanocomposites. Wear tests were performed on MMT/epoxy nanocomposites with four different clay concentration levels to characterize the improvement in wear behavior due to the MMT concentration. In order to examine the tribological mechanism depending on the clay concentration level, SEM analysis was performed on the worn surfaces after the wear tests. The results showed that the friction coefficient of an MMT/epoxy nanocomposite with a low MMT concentration was larger than that of a nanocomposite with a high MMT concentration. It is believed that the phenomena occur due to the action of MMT as a reinforcement and lubricant material and reduce the wear rate with increasing MMT concentration.


Friction ◽  
2021 ◽  
Author(s):  
Xiaogang Zhang ◽  
Yali Zhang ◽  
Zhongmin Jin

AbstractNumerous medical devices have been applied for the treatment or alleviation of various diseases. Tribological issues widely exist in those medical devices and play vital roles in determining their performance and service life. In this review, the bio-tribological issues involved in commonly used medical devices are identified, including artificial joints, fracture fixation devices, skin-related devices, dental restoration devices, cardiovascular devices, and surgical instruments. The current understanding of the bio-tribological behavior and mechanism involved in those devices is summarized. Recent advances in the improvement of tribological properties are examined. Challenges and future developments for the prospective of bio-tribological performance are highlighted.


2018 ◽  
Vol 55 (1) ◽  
pp. 102-110 ◽  
Author(s):  
Marian Bastiurea ◽  
Dumitru Dima ◽  
Gabriel Andrei

Graphene oxide and graphite filled polyester composites were prepared by using conventional melt-mixing methods in order to improve tribological performance of polyester. It was investigated friction stability, microhardness, friction coefficient, and specific wear rate of the composites in details. It was found that the presence of graphite and graphene oxide influenced friction coefficient and wear rate of the composites. Graphene oxide decreased wear rate with increasing of test speed and graphite decreased wear rate for composite for all speeds. Tribological performance of the polyester/graphene composites is mainly attributed to bigger thermal conductivity for graphene, which can easily dissipate the heat which appears during the friction process at bigger forces. The positive influence of graphite on coefficient of friction (COF) of the composites is the result of the clivage of graphite layers during the loadings due to van der Waals weak bonds between the graphite layers.


Author(s):  
M. Kameswara Reddy ◽  
V. Suresh Babu ◽  
K. V. Sai Srinadh

The present work studies the tribological performance of Tungsten Carbide (WC) nanoparticles reinforced epoxy polymer nanocomposites. Polymer nanocomposites are prepared by hand lay-up method. Erosive wear and hardness tests were conducted to examine the physical and wear properties of epoxy/WC nanocomposites. Addition of WC nanoparticles led to significant reduction in erosion rate. In addition to that, incorporation of WC nanoparticles enhanced the hardness of epoxy nano composites. At 2% weight of WC nano filler, nanocomposites showed better performance in erosion wear properties and also in hardness. While at 3wt% of WC filler, least performance in hardness was caused by the weak adhesive bonding between the matrix and filler. The nature of erosion wear behavior was observed. Finally worn surfaces of nanocomposites were inspected using a “scanning electron microscope (SEM)”.


2018 ◽  
Vol 70 (4) ◽  
pp. 764-772 ◽  
Author(s):  
Nikolai K. Myshkin ◽  
Alexander Kovalev

Purpose The purpose of this paper is to review the advances in mechanics and tribology of polymers and polymer-based materials. It is focused on the understanding of the correlation of contact mechanics and the tribological behavior of polymers and polymer composites by taking account of surface forces and adhesion in the contact. Design/methodology/approach Mechanical behavior of polymers is considered a viscoelasticity. Tribological performance is estimated while considering the parts of deformation and adhesion in friction arising in the contact. Surface energy, roughness, load and temperature effects on the tribological behavior of polymers are evaluated. Polymer composites produced by reinforcing and by the addition of functional additives are considered as materials for various applications in tribology. Particular attention is given to polymer-based nanocomposites. Findings A review of studies in tribology has shown that polymer-based materials can be most successfully used as self-lubricating components of sliding bearings. The use of the fillers provides changes in the tribological performance of neat polymers and widens their areas of application in the industry. Thin polymer films were found to be prospective lubricants for memory storage devices, micro-electro-mechanical systems and precision mechanisms. Further progress in polymer tribology should be achieved on solving the problems of contact mechanics, surface physics and tribochemistry by taking account of the scale factor. Originality/value The review is based on the experience of the authors in polymer mechanics and tribology, their research data and on data of many other literature sources published in this area. It can be useful for specialists in polymer research and industrial engineers working in tribology and industrial lubrication.


2019 ◽  
Vol 26 (07) ◽  
pp. 1850217 ◽  
Author(s):  
O. ÇOMAKLI ◽  
A. F. YETIM ◽  
B. KARACA ◽  
A. ÇELIK

The 31CrMoV9 steels were plasma nitrided under different gas mixture ratios to investigate an influence of nitrogen amount on wear behavior. The structure, mechanical and tribological behavior of untreated and nitrided 31CrMoV9 steels were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), microhardness device, 3D profilometer and pin-on-disk wear tester. The analysis outcomes displayed that the compound layer consists of nitride phases (Fe2N, Fe3N, Fe4N and CrN). Additionally, the thickness of the compound layers, surface hardness and roughness increased with increasing nitrogen amount in the gas mixture. The highest friction coefficient value was obtained at nitrogen amount of 50%, but the lowest value was seen at nitrogen amount of 6%. It was observed that wear resistance of 31CrMoV9 steel improved after plasma nitriding, and the best wear resistance was also obtained from plasma nitrided sample at the gas mixture of 94% H[Formula: see text]% N2.


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