Modification of the mechanical properties of rubbers by introducing recycled rubber into the original mixture

In our experimental work the opportunities of improving of mechanical properties of rubbers and their
composites have been investigated. On the one hand the reuse of milling product of recycled
rubbers (recycled crumb rubbers) has been studied and the effects of the filler and compatibilizers
applicable in rubber composites on the mechanical properties either. The rubber composites were
exposed to different mechanical stresses (tensile, fatigue tensile) and Shore A hardness and density
of the specimens have also been determined. Morphology of the composites and the interaction
between the fillers and the rubber has been studied on SEM graphs. Recycled crumb rubber was
added in different concentrations to the basic mixture of rubber. Significant improvement of
mechanical properties could be achieved by mixing 22m/m% used crumb rubber to the basic
mixture. Tensile strength at break of composites containing recycled crumb rubber increased with
nearly 20% compared to the original basic mixture containing no crumb rubber. Density decreased
with 2-3% and Shore A hardness with 6% comparing the aforementioned composites. Different
types of compatibilizing additives have also been applied in the system containing crumb rubber
which showed different effectiveness in case of the properties, e.g. tensile strength at break. Adding
compatibilizing additives to the basic mixture of rubber did not make the density changed while
Shore A hardness changed similarly to the trend observed in case of tensile strength at break.