## 1 Introduction  
The global problem of the accumulation of used tires as stores [1; 2] has driven the efforts of the scientific community to search for solutions for recovery and reuse of this wasted material. The use of this ground tire rubber (GTR) as reinforcements in composite materials has been widely studied in several works [3]. The presence of GTR in polymer matrix composite materials modifies both the dielectric and mechanical behavior. In general, a thermoplastic or thermosetting polymer acts as a matrix and the elastomer acts as a dispersed phase [4; 5; 6]. Moreover, as in other two-phase polymer blends, as composites [7; 8], the interfacial compatibility between the components is important for achieving the desired properties. In the case of recycled elastomers, expected compatibility is low. One way to increase the compatibility between components is to reduce the degree of cross-linked GTR by devulcanization [9; 10; 11]. Significant changes in properties are observed when we change the size of the reinforcement particles [12].  
In previous investigations [13], it has been shown that there are better mechanical properties for samples with particle diameter under 200 \(\upmu\)m than for particles between 200 and 500 \(\upmu\)m. The worst mechanical properties are observed for diameters greater than 500 \(\upmu\)m. Thus, this research is focused on particles of GTR whose diameter is under 200 \(\upmu\)m. Assuming a possible worsening in the mechanical properties of the polymer matrix when mixing with GTR, our goal is to determine what percentage of GTR can be added to a set of polymeric matrices (PVC, EVA, HDPE, PP, PA, ABS, and PS), keeping the mechanical properties within an acceptable range of values, as well as the polymer initial microstructure [14]. This would allow the addition of GTR to various industrial processes, and the recycling of this wasted material. To this end, we have analyzed various concentrations of polymer/GTR (from 0% to 70% of GTR) with the indicated particle size. Finally, we will give some applications that could use these compounds analyzed.  
The GTR constitutes the reinforcing agent here. In this way, the GTR would not serve in the applications of high requirements that polymers already have. Most polymeric materials have very good properties as insulating materials, with conductivity values under 10\({}^{-12}\) S\(\cdot\)cm\({}^{-1}\). It is known that with the incorporation of conductive additives such as graphite, carbon black, metallic oxides, and so forth, the conductivity is significantly improved. Without a doubt, carbon black is the most common and easily handled additive; previous investigations [15] have observed that the presence of carbon black and fiberglass, as reinforcement in composite materials, increases both the mechanical properties and the electrical behavior. Composite materials are heterogeneous and their properties depend on the quantity, size, and shape of the reinforcement, as well as other factors such as the preparation thereof, as well as compatibility. Other researchers [16; 17] have studied different samples of materials with different compositions and variable proportions of additives such as carbon black (CB).