Erosion-wear, mechanical and thermal properties of silica filled epoxy nanocomposites

Significance Statement

Epoxy resin is rather brittle, but has high modulus, strength, superior adhesion strength, and low creep, which makes it attractive for several industrial productions. Epoxy resins are used for anti-cavitation painting. Cavitation is the mechanical degradation of a surface reference to the continuous collapsing on it of bubbles and cavities from a surrounding liquid. Cavitation therefore affects the operation of hydraulic devices such as valves, ship propellers, fittings, hydroelectric turbines, and hydraulic pumps.
As mentioned previously, epoxy resins are brittle and this is the reason why varying percentages of nanoparticles are applied as fillers. Silica nanoparticles, for instance, can be used to increase fracture toughness. In addition, cork microparticles can also be used to reduce the brittleness of epoxies or natural fibers. Researchers have therefore; focused on micro and nanoparticles as they enhance the mechanical attributes, thermal characteristics, wear resistance, and the curing reaction of epoxy resins.
Pyrogenic silica can be used as a filler in urethane-acrylic that is normally adopted as a coating in polycarbonate substrates in order to enhance wear resistance. Amorphous silicon oxide has also been used as the main thixotropic agent in the synthesis of anaerobic adhesives. In the recent studies, silica has been applied to synthesize polyurethane nano-adhesives. This is because silica nanoparticles improve the nano-adhesives Young’s Modulus as well as tensile strength.
Reference to the applications of nano-silicon oxide and epoxy, Juana Abenojar , Miguel Angel Martínez at Universidad Carlos III de Madrid in collaboration with Joaquin Darío Tutor-Sáncehz, Juan Carlos del Real and Yolanda Ballesteros at Universidad Pontificia Comillas in Spain analyzed the performance of Silicon oxide/epoxy nanocomposites subjected to wear and erosion. They justified this performance with thermal and mechanical properties with unmodified nano silicon dioxide. Their research work is published in journal, Composites Part B.
The focus of the current study was on the effect of pyrogenic silica on epoxies, normally not present in their assemblages. The researchers manufactured silicon dioxide/epoxy nanocomposites with two loads of nano silica; 3 wt% and 5 wt%. Their aim was to establish the effect that the inclusion of nano-silica has on wear, mechanical and cavitation erosion, and thermal attributes, and curing reaction. To meet these objectives, the authors prepared nanocomposite specimens as coatings and in bulk. They later evaluated bending and tensile strength, hardness, wear resistance, and cavitation erosion.
The authors observed that the inclusion of nanoparticles affected the wear resistance. They found that nanocomposites with 5% of silica should not have been used for applications requiring high wear resistance. A lubricating effect observed at 1000m sliding distance indicated that a lower content of silica, about 3%, should have been used, particularly for ‘in-bulk’ applications.
It was observed that all cavitation erosion parameters were reduced when silica was added. However, additions of 3-5% did not give an appreciable difference. The improvement in the cavitation resistance could be traced to the increment in root shape fractures as well as plastic deformation in some areas. The inclusion of silica made the composite to have less strength and hardness, but became more ductile. When a large percentage was added, the value of the Young’s Modulus was observed to reduce.
Lower values of transition temperature indicated that the nanocomposites plasticized more with respect to the clear resin. Plasticization was in keeping with the strength and hardness loss and augmented ductility. Nanoparticles also affected the curing process. They promoted the preliminary curing mechanism, but in high amounts hindered crosslinking, therefore, inhibiting the overall curing.

Erosion-wear, mechanical and thermal properties of silica filled epoxy nanocomposites-Advances in Engineering

About the author

Juana Abenojar studied Chemistry at Universidad Complutense de Madrid (Spain) and received her Ph.D. in Materials Science and Engineering at Universidad Carlos III de Madrid (Spain) in 2003. Currently she is researcher in Material Performance Group of this University and participates in numerous regional, national and European R&D projects. Besides, she is author/co-author of more than 70 research papers in journals included in JCR and she has attended numerous national and international conferences. Her research interests include on powder technology, surface treatments, developing materials for nuclear applications, polymer composites and adhesives.
She is Member of the Coordinating Committee of the Spanish Adhesion and Adhesives Group (GEAA) and the Scientific Committees of “International Congress of Adhesion and Adhesives” and “International Conference on Fracture, Fatigue and Wear”

About the author

Joaquin Darío Tutor-Sáncehz was Associate Professor in the Department of Mechanical Engineering at the ETSI-ICAI School of Engineering of the Universidad Pontificia Comillas, Spain, until 2016. Nowadays he is Technical Director, R&D, at the Laboratory of Analysis and Essays of Thermal Chain (LAECT). PhD degree in Theoretical Physics since 1995 from the Physics Faculty of Havana University, Cuba.

He develops his research activity in the field of Advanced Materials and Nanomaterials with applications to Thermal Chian Technology. He is Coordinator of the International Network for Dissemination and Training on Nanotechnology, NANODYF, and member of the Editorial Advisory Board of the Revista Escuela de Ingeniería de Antioquia, EIA, Colombia.

About the author

Juan Carlos del Real is a professor in the Department of Mechanical Engineering with the ICAI School of Engineering at Universidad Pontificia Comillas. PhD degree in Industrial Engineering from the Universidad Pontificia Comillas (ICAI. He develops his research activity in the field of Advanced Materials and Nanotechnology.

He has been President and is currently Scientific Coordinator of the Spanish Adhesion and Adhesives Group (GEAA) and member of the Editorial Advisory Board of the Journal of Adhesion and Applied Adhesion Science.

About the author

Miguel Angel Martínez studied Chemistry at Universidad Complutense de Madrid (Spain). He has a PhD in Chemistry (in 1989) at Universidad Complutense de Madrid. He is professor at Universidad Carlos III de Madrid since 1995. He has carried out research in sintered materials, surface treatments, developing materials for nuclear applications, adhesives, surface treatments and organic coatings. He has published 80 papers in journals included in JCR and he has managed funds from regional and national and he has participated as researcher in European R&D projects. He has supervised 5 PhD Thesis.
He is President of the Coordinating Committee of the Spanish Adhesion and Adhesives Group (GEAA) and Member of the Scientific Committees of “International Congress of Adhesion and Adhesives” and “International Conference on Structural Adhesive Bonding”

About the author

Yolanda Ballesteros is a professor in the Department of Mechanical Engineering of the ICAI Higher Technical School of Engineering at the Universidad Pontificia Comillas. PhD in Sciences (1997) and Bachelor’s Degree in Chemistry (1985-1990) from the Autonoma University of Madrid (UAM), she is currently Head of the Chemistry, Materials and Environment Laboratory in ICAI. She is part of the Interuniversity Research Group on Structural Adhesives, made up of researchers from ICAI and the University Carlos III of Madrid. Since March 2011 she has been developing her research activity in the Institute of Technological Research (IIT) in the line of advanced materials and nanotechnology.

She has participated in several R+D+i projects for different industrial sectors and public financing. The actual research lines include: adhesives, non-destructive tests, biomaterials, composite materials and nanomaterials.

Reference

J. Abenojar *, J. Tutor, Y. Ballesteros, J.C. del Real, M.A. Martínez. Erosion-wear, mechanical and thermal properties of silica filled epoxy nanocomposites. Composites Part B, volume 120 (2017), pages 42-53.

Go To Composites Part B

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