mechanical strength [7]. In this respect, ferrites are considered to be the best magnetic material for electromagnetic wave absorbers thanks to their outstanding magnetic and dielectric properties. However, they are heavy and expensive. In other respects, polymers are used to protect the electronic devices from electromagnetic interference (EMI) due to the flexibility, lightweight and cost effectiveness. Nevertheless, polymers are electrically insulating and transparent to electromagnetic wave. Therefore, ferrite materials are incorporated into polymer matrices to effectively eliminate EMI [8]. Many works have been done on polymer-based composites filled with magnetic materials in micrometer – size, such as Fe3O4/YIG [9]. However, conventional magnetic particles filled polymer-based composites have some drawbacks in corresponding the criterion in thin and lightweight microwave absorber because of high filler content [10]. Fe3O4 nanoparticle, was selected in this study mainly due to its genuine and novel physiochemical properties which can be attained according to their particle size (quantum size effect), morphology, shape and engineering form [11]. Also, it is found attractive to enhance the magnetic permeability of epoxy based composites, accordingly obtaining a good synchronization between the electrical and thermal conductivities [12]. Moreover, addition of Ni and Fe3O4 thermite powder mixtures to the matrix has been shown to have significantly affect the energetic of the reaction between the powders [13]. A balanced mixture of these characteristics can result in superior structural and energetic properties. In this paper, preliminary results have been presented for the design procedure of an epoxy-scrap rubber matrix composite with the exothermic reinforcements mentioned above. During this experimental study, nano wear and creep behaviour were examined by means of nano-indentation technics. Compression tests were performed for mechanical characterization. In addition, surface hardness was determined by means of Shore D hardness measurement. Furthermore, impact behaviour was investigated by means of dynamic compression tests (drop weight testing). After all the tests and analyses, scanning electron microscopy (SEM) was used to observe the fracture surfaces and microstructure to study the distribution of different reinforcements and damage characteristics. 4.2 Experimental Conditions 4.2.1 Materials Processing As well-known, epoxy resin and scrap rubber powder (already vulcanized) cannot make a chemical bonding. For this reason, scrap rubber powder should be treated with a chemical solution to activate surface of rubber powder and try to make a good mixture with epoxy resin powder. In the frame of the present work, recycling of rubber is aimed for the manufacturing of low cost composites for aeronautical and automotive applications. Scrap rubber powder was sent by sporting good company (sport shoes, etc.). At the first stage, a chemical-Silanization treatment was used to make a strong bonding very fine dry epoxy powder and fine scrap rubber powder (Styrene–butadiene rubber (SBR). Meanwhile, using of recycled rubber gives an economic perspective to this study. Epoxy and rubber were mixed by using blending and mortar mixture then dried in an oven to entirely eliminate humidity and also traces of chemicals due to treatment. This mixture was milled for an hour to obtain a homogeneous compound and then it was heated at 80 C for 24 h. The resulting compound was used as the matrix for the proposed composites. In the second stage, the reinforcements Ni and Fe3O4 were added to the matrix in pre-defined ratios. All of the compounds were then mixed in a blender and milled again by Fritsch®Pulverisette2 for 4 h. Longer milling times result in over heating of the mixture and this phenomenon influences the material properties. After that, the specimens (called as ENRF I-II hereafter) were manufactured by hot compacting (double uniaxial action) under a pressure of 70 MPa at 180 C. The dwell time for compacting process was 15 min. All of the specimens (30 mm & 50 diameters, 5–6 mm thickness) were cooled down slowly. The post curing was concluded under isothermal conditions at a temperature of 80 C for 24 h. General compositions of all the composites manufactured here are given in the Table 4.1 with specified weight ratios for each constituent. Table 4.1 Composition of the epoxy-rubber based composites Epoxy-Rubber based composition Epoxy – SBR rubber (10 phr) ENRF I ENRF II Reinforcements (wt %) 10 (Fe3O4) 5 nickel 20 (Fe3O4) 5 nickel 34 A.B. Irez et al.
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