It is realized that the addition of a small percentage of rigid nanoparticles to polymers significantly improves many of their mechanical properties, especially stiffness and strength. Such improvements are often attributed to the availability of large numbers of nanoparticles with huge interfacial areas compared to their macro- and micro-scale counterparts. In particular, from the tribological viewpoint, the small size of nanoparticles with homogenous dispersion in the matrix and good interfacial adhesion between nanoparticles and matrix are thought to be necessary requirements for a polymer nanocomposite. Material removal will be less since the nano-additives have similar sizes to the segments of surrounding polymer chains. Despite these positive effects due to the addition of nanoparticles, there are still some critical questions that are unanswered. Here, we review the fundamentals, recent progress and advances that have been made on the tribological aspects of polymer nanocomposites, particularly focusing on their wear (in dry sliding and unlubricated conditions) and scratch damage. The review shows that (a) it is not valid to assume that nano-fillers always improve wear/scratch (and friction) properties; and (b) material properties like modulus, hardness, fracture toughness or extent of wear rate or scratch penetration depth are not the sole indicators to compare and/or rank candidate materials. Several facets of wear/scratching or material response to the sliding processes require thorough understanding in order to determine parameters that control the surface integrity and material removal from polymer nanocomposites. This review also shows the apparent contradictions and false impressions on several material systems in many studies owing to poor characterizations of polymer nanocomposites and lack of quantitative descriptions of the observed phenomena.
This second edition of Nanocrystalline Materials provides updated information on the development and experimental work on the synthesis, properties, and applications of nanocrystalline materials. Nanocrystalline materials with new functionalities show great promise for use in industrial applications - such as reinforcing fillers in novel polymer composites - and substantial progress has been made in the past decade in their synthesis and processing. This book focuses primarily on 1D semiconducti...
#1Rocío Seltzer(USYD: University of Sydney)H-Index: 12
#2Yiu-Wing Mai(USYD: University of Sydney)H-Index: 112
Abstract Viscoelastic solids may deform plastically under indentation. This leads to an overestimation of the creep compliance when the analytical solution for indentation of linear viscoelastic materials [Lu H, Wang B, Ma J, Huang G, Viswanathan H. Measurement of creep compliance of solid polymers by nanoindentation. Mech Time-Depend Mater 2003;7(3–4):189–207] is used for its determination. Using finite element analysis, in this work it is shown that the plastic and viscoelastic deformation pro...
Abstract The objective of the study is to understand the nanoscale near-surface deformation response of two polymer nanocomposite systems with significant differences in ductility during nanoscratching with a Berkovich indenter using a load of 1 mN and a scratch velocity of 1 μm s −1 . An accompanying objective is to investigate the commonality in surface deformation behavior between nano- and microscale deformation to reinforce the underlying fundamental principles governing surface deformation...
Polyacrylonitrile-methylmethacrylate-carbon nanotubes (AMMA-CNTs) copolymer nanocomposites with different contents have been prepared by means of in situ polymerization process successfully. The AMMA-CNTs copolymer nanocomposites are desirable for many important applications. We measured the microhardness of the AMMA-CNTs copolymer nanocomposites. It was found that CNT could increase the microhardness of the nanocomposites effectively. A friction and wear tester under dry conditions investigated...
#2Zhong-Zhen Yu(USYD: University of Sydney)H-Index: 61
Last. Jang Kyo Kim(HKUST: Hong Kong University of Science and Technology)H-Index: 100
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The major objectives of this work are to understand the effects of organoclay, its extent of exfoliation and orientation, and indenter geometry on the scratch characteristics of polyamide 6/organoclay nanocomposites. Two different organically treated clays are used for this purpose and their structural parameters in a polyamide 6 matrix quantified. It is shown that, while the material properties are important for scratching resistance, they are not the only determinants of the scratch performanc...
#1Qinghua Zeng(UNSW: University of New South Wales)H-Index: 21
#2Aibing Yu(UNSW: University of New South Wales)H-Index: 97
Last. Gao Qing Lu(UQ: University of Queensland)H-Index: 118
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Polymer nanocomposites offer a wide range of promising applications because of their much enhanced properties arising from the reinforcement of nanoparticles. However, further development of such nanomaterials depends on the fundamental understanding of their hierarchical structures and behaviors which requires multiscale modeling and simulation strategies to provide seamless coupling among various length and time scales. In this review, we first introduce some computational methods that have be...
#2Bharat Bhushan(OSU: Ohio State University)H-Index: 135
Abstract Various mechanisms of solid–solid and solid–liquid friction are studied in this review, and their relation to the surface roughness hierarchy is discussed. For ideal solid bodies with conservative forces acting between them, there would be no friction. Different deviations from the ideal state, such as the surface roughness, contamination and chemical heterogeneity, bulk material deformation and non-conservative adhesive bonds, lead to energy dissipation. Most heterogeneities involved i...
#1Seong H. Kim(PSU: Pennsylvania State University)H-Index: 58
#2David B. Asay(PSU: Pennsylvania State University)H-Index: 15
Last. Michael T. Dugger(SNL: Sandia National Laboratories)H-Index: 27
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The tribological phenomena of adhesion, friction, and wear arise when solid objects make contact. As the size of devices shrinks to micro- and nanoscales, the surface-to-volume ratio increases and the effects of body forces (gravity and inertia) become insignificant compared with those of surface forces (van der Waals, capillary, electrostatic, and chemical bonding). In microelectromechanical systems (MEMS), tribological and static interfacial forces are comparable with forces driving device mot...
#1Jacqueline Krim(NCSU: North Carolina State University)H-Index: 42
The ability to predict sliding friction in an adsorbed film system is key to a vast range of fundamental and applied issues in physics and nanotechnology. Sliding friction levels in molecularly thin layers can be measured experimentally by means of the quartz crystal microbalance (QCM) technique, which is readily comparable to theory, including both analytic calculations and molecular dynamics simulations. Progress in this area is summarized here, focusing on fundamental energy dissipation mecha...
#1Wengui Li(UTS: University of Technology, Sydney)H-Index: 32
#2Zhiyu Luo(UTS: University of Technology, Sydney)H-Index: 11
Last. Surendra P. Shah(UTA: University of Texas at Arlington)H-Index: 114
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Abstract null null Interfacial transition zones (ITZs) of cementitious concrete are highly heterogeneous, which cause many challenges in accurately obtaining their properties. In this paper, regular aggregates were applied to prepare modelled geopolymer composites, in which ITZs exhibited neat boundaries. Nanoscratch technique with the ability to quickly scan a long distance was adopted to investigate mechanical properties of ITZ and geopolymer paste. To compare the properties of the ITZs and pa...
Last. Chaoqun Xia(HEBUT: Hebei University of Technology)H-Index: 8
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Abstract Aluminum (Al)-based amorphous alloys (hereinafter abbreviated as AAA) with good mechanical and anti-corrosion properties are ideal fillers for modified organic coatings. A novel polyurethane (PU)/Al/AAA composite coating was prepared by adding Al-based alloy powders, which were composed of Al and AAA powders. The effects of Al or AAA powder concentration on the mechanical behavior, corrosion resistance and infrared (IR) emissivity of PU/Al/AAA coatings were systematically investigated a...
#1Ji-nian Yang(Anhui University of Science and Technology)H-Index: 6
#2Yu-xuan Xu(Anhui University of Science and Technology)H-Index: 2
Last. Jiang Liu(Anhui University of Science and Technology)
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Abstract null null The present study aims at investigating the effect of organic-modified nickel phyllosilicate (NiPS) particles on the structure-property relationships of epoxy (EP) composites. The organic-modified NiPS particles were synthesized using a facile sol-gel method and subsequently mixed into EP matrix by physical blending to improve its tribological, mechanical and thermal properties. Based on a series of tests and analyses, it was found that organic-modified NiPS particles playing ...
#1Ji-nian Yang(Anhui University of Science and Technology)H-Index: 6
#2Xue-song Feng(Anhui University of Science and Technology)
Last. Zhen-yu Li(Anhui University of Science and Technology)H-Index: 2
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The nanocomposites of flower-like nickel phyllosilicate particles incorporated into epoxy resin were fabricated via an in-situ mixing process. The flower-like nickel phyllosilicate particles were firstly synthesized using a mild self-sacrificial templating method, and the morphology and lamellar structure were examined carefully. Several properties of mechanical, thermal and tribological responses of epoxy nanocomposites were performed. It was demonstrated that adequate flower-like nickel phyllo...
#1Santosh Kumar(IITs: Indian Institutes of Technology)H-Index: 96
#1S. Kumar(IITs: Indian Institutes of Technology)H-Index: 1
Last. J. Ramkumar(IITK: Indian Institute of Technology Kanpur)H-Index: 1
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Over the last decade, FRP composites have seen increased use in many applications, where an optimum combination of light-weight, better wear resistance and excellent mechanical properties have attr...
Last. Li Chang(USYD: University of Sydney)H-Index: 24
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Abstract In this present work, the sliding wear behaviour of hybrid polymer nanocomposites was investigated under different loading conditions and against different counterface roughness. Two different polymers matrices, epoxy and polyamide 66, with classic micro-sized short carbon fiber and graphite flakes as tribo-fillers were investigated with and without TiO2 reinforcing nanoparticles. It was found that the synergistic effect between nanoparticles and micro-sized fillers on friction and wear...
Abstract The present paper aims to introduce a novel approach to fabricate hybrid polymer nanocomposite coating containing epoxy/polyurethane blend, multi-walled carbon nanotubes (MWCNTs) and SiO2 nanoparticles. For this purpose, MWCNTs and SiO2 nanoparticles were first functionalized with silane and silyl compounds, respectively, and then mixed with epoxy resin and polyurethane prepolymer along with dimethylthiotoluenediamine (DMTDA) as hardener. Eventually, the nanocomposite coatings containin...
The influence of 0.5, 0.75, and 1 wt.% of graphene oxide (GrO) in nanocomposite coating on scratch behavior and tribological performance was analyzed. Graphite was oxidized using the Marcano and Tour method to obtain graphite oxide, which is thermally exfoliated at 700°C getting graphene oxide. The transformation of graphite to graphene oxide was evaluated via Raman spectroscopy and X-ray diffraction. Effects of graphene oxide content on the friction and wear behavior of polyester composite coat...