1.1.2. FillersDifferent fillers such as carbon black (CB), precipitated silica, and clay have been used in rubber formulation to improve the rubber strength. This is done via the formation of a flexible filler network and strong polymer-filler interactions [6]. Stiffening fillers (CB and silica) improve rubber stiffness, tensile and tear strength, hardness, and rupture modulus as a result of increased chain entanglements and shear strength between the polymer chains. Montmorillonite, synthetic mica, and saponite are clay-based fillers used in rubber production due to better mechanical properties’ improvement compared to CB [7]. For example, Okada [8] reported the positive effect of 10 vol.% of organoclay in NBR to achieve similar tensile strengths as rubber formulations with 40 vol.% CB. However, the rubber microstructure might be affected by the size, shape, and molecular structure of the fillers