Chapter 4 Toughening Mechanism in Epoxy Resin Modified Recycled Rubber Based Composites Reinforced with Gamma-Alumina, Graphene and CNT A. B. Irez, E. Bayraktar, and I. Miskioglu Abstract In this research, low cost devulcanized recycled rubber based composites were designed with fine gamma alumina (d < 5–10 μm) reinforcements containing minor reinforcements such as nano graphene platelets and Carbon Nano Tubes. After determination (in different wt% percentages) of the reinforcements with matrix, a special process was applied to complete successfully the manufacturing of the composites. After that, the relevant toughening mechanisms for the most suitable reinforcements were analyzed in detail for aeronautical engineering applications. For this purpose, certain mechanical and physical properties (ISO 13586:2000, KIc – Fracture toughness stress intensity factor and GIc- Critical energy release rate in mode I) have been determined by fracture toughness tests (static 3P bending test with single edge notch specimens, Charpy impact, etc.). Microstructural and fracture surfaces analysis have been carried out by means of Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). Keywords Epoxy · Recycled rubber · Wear resistance · SEM· Fracture toughness 4.1 Introduction Rubber is generally used in different engineering applications as strategic materials and it is manufactured by using reinforcements for multifunctional composites and/or hybrid composites with higher thermal, magnetic, electric and other properties, etc. Last decades, very useful nano scale reinforcements are used extensively for the manufacturing of high performance rubber based composites that they are environment-friendly. Among these reinforcements, Graphene (GnPs) and/or graphene oxide (GO) together with Carbon Nano Tubes (CNTs) have appeared in the global market as a new alternative nano-scale materials with high static and dynamic mechanical and physical properties against Carbon blacks (CBs). They are very cheap, clean and easily produced safely by incorporating in a matrix, such as styrene-butadiene rubber (SBR) and natural rubber, etc. However it is not easy to distribute them homogenously in the matrix with traditional mixing methods such as mechanical blending [1–4]. In another aspect, utilization of the recycled rubber for the manufacturing of the new composites is a very economical way for cost effective composite design. Last decades, the usage of the recycled rubber obtained from fresh and clean scrap rubber for different industrial applications such as automotive and aeronautical engineering has been very well developed as very useful material for the composites either as a matrix or as a reinforcement. Extensively, this rubber powder come directly manufacturing of sportive affaires, shoes etc., For this reason, it is feasible to use it after chemical (silanization) and devulcanization treatments for cost effective composite design [3–9]. Reinforcement of the rubber based composites with nano graphene and/or graphene nano plates (GnPs) are very extensive applications in composite design for mainly aeronautic and aerospace applications. Graphene are known and used widely used as multi- functional reinforcement materials that can improve the electrical, piezo-resistive, dielectric, thermal and other physical and mechanical properties of rubber based composites with hybrid fillers. Because of the exceptionally high surface A. B. Irez CentraleSupélec, Université Paris-Saclay, Gif-sur-Yvette, France E. Bayraktar ( ) Supmeca-Paris, School of Mechanical and Manufacturing Engineering, Saint-Ouen, Paris, France e-mail: bayraktar@supmeca.fr I. Miskioglu Michigan Technology University, Engineering Mechanics Department, Houghton, MI, USA © The Society for Experimental Mechanics, Inc. 2019 P. R. Thakre et al. (eds.), Mechanics of Composite, Hybrid and Multifunctional Materials, Volume 5, Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-319-95510-0_4 31
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