## 3 Results and Discussion  
### Mechanical Properties  
Mechanical Comparative of All Seven Polymers/GTR  
As we can see in the Figure 6a,b and Figure 7a,b analyzed, the addition of old, used tire particles in all compounds produces a decrease in the four mechanical properties analyzed in general like Young's modulus (Figure 6a) and tensile strength (Figure 6b) elongation at break (Figure 7a) and toughness (Figure 7b). For the Young's modulus analysis, we can see how the PVC and EVA compounds have better behavior with the addition of the GTR percent in the composite, and in the tensile strength analyzed, we can see how the PA and PVC compounds have better behaviors with the addition of quantities of GTR (near 70%). From the observation of the comparative graph of the [PERSON]'s modulus (Figure 6a), it can be deduced that the analyzed materials have comparable characteristics of the [PERSON]'s modulus. Of all of them, those with a higher Young's modulus are: PVC, PA, and ABS (3028.89, 2841.47, and 2522.37 MPa, respectively). Highlighted, the PVC polymer reaches 3028.89 MPa, and secondly, and in a range of very similar values, the PA polymer (2841.47 MPa) is located. With the addition of GTR particles, in general, the properties of [PERSON]'s modulus fall. It must be said that, in general, comparatively, the polymer with the best properties of the [PERSON]'s modulus is PVC, and with percentage of GTR of 20%, a good behavior of the [PERSON]'s modulus is observed for particle sizes \(<\)200 \(\upmu\)m (2225.87 MPa); however, for percentages of GTR greater than 20% (40%, 50%, 70%: 2005.87, 1900, 1627 MPa, respectively), the behavior of the Young's modulus drops to values close to 40% of the value of the polymer without additive. The analyzed composites, in general, have worse behaviors of the Young's modulus with the addition of GTR, except for the PS and the HDPE composites, for which the addition of GTR  
Figure 6: (**a**) Young’s modulus (MPa), (**b**) tensile strength (MPa), for seven polymers/GTR concentrations and particle size \(<\)200 \(\upmu\)m.  
positively affects these composites (PS, HDPE), increasing the Young's modulus for percentages of GTR of 5, 10, 20%. A very prominent case is the EVA copolymer, which has very low Young's modulus properties (13.26 MPa) which improves with the incorporation of GTR (41.67 MPa for EVA + 10% GTR). In the comparative graph of tensile strength (Figure 6b), it can be deduced that the materials analyzed have comparable characteristics of resistance to breakage. Of all of them, those that have a greater resistance to breakage are: PA, ABS, PS, and PVC. In a very prominent way, the PA polymer reaches 50.41 MPa, and in second place is the ABS polymer (44.98 MPa) from the addition of GTR particles, the properties of resistance to breakage (5% GTR), the following value of breaking strength is obtained: 19.67 MPa; this is the exception found in the present analysis. In general, small percentages of GTR additive (5%) result in worse behavior of tensile strength. Comparatively, the polymer with the best breaking strength properties is the PA and with percentages of GTR of up to 20%, a good behavior of the breaking strength (47.39 MPa) is observed, however, for percentages of GTR greater than 20% (40%, 50%, 70%), the behavior of the breaking strength drops to values close to values of 50% breaking strength of the polymer without additive. For the rest of the materials, it can be deduced that, in general, they have good breaking strength behaviors, although for PS and EVA (38.89 MPa and 23.08 MPa, respectively), the addition of GTR negatively affects these properties, and they suffer a certain drop in breaking strength for percentages higher than 20% of GTR (40%, 50%, 70%).