Investigation of the effect of carbon black on the properties of chloroprene/butadien rubber blends

In the rubber industry, especially in the tire manufacturing sector, carbon black and silica are generally used as fillers. Fillers are added to mixtures for both reinforcing and cheapening purposes. Therefore, fillers improve physical properties both in vulcanized and dough form. In the case of fillers, it is known that the effectiveness of the reinforcement depends on the complex interaction of several parameters related to the filler. These include particle size, particle shape, particle distribution, surface area, surface reactivity, structure of the filler and bonding quality between the filler and the rubber matrix. In this study, chloroprene and butadiene rubber mixtures were prepared and the effect of carbon black concentration on rheological, physical and mechanical properties in CR/BR dough was investigated. While preparing these mixtures, carbon black was added at different rates (25-75 phr) and particle sizes (~ 28-350 nm) together with optimum levels of process facilitators, ozone protectors, antioxidants, accelerators, activators and vulcanization agents. Rubber mixtures with different compositions were mixed in a laboratory type closed mixer and open shaft. The rheological properties of the materials were determined in the rheometer device and test plates were printed according to the optimum vulcanization times. The tensile strength and percentage elongation of the materials were determined according to the ASTM D 412-87 standard. When the materials containing different amounts of carbon black were evaluated within themselves, the increase in the minimum and maximum torque values with the increase in the filler ratio showed that the matrix-filler interaction was strengthened. The density of the composite without carbon black was 1.35 g/cm3 and the hardness value was 46 Shore A. The density values (1.37-1.46 g/cm3) increased with the addition of carbon black. It was determined that the hardness increased (49-87 Shore A) as the amount of carbon black increased, regardless of the type of carbon black. While the percentage elongation values decreased as the amount of carbon black increased, the tensile strengths varied according to the loading rate. When the permanent deformation properties were examined, it was observed that the permanent deformation was relatively improved as the carbon black particle size decreased. The results of this research provided important data on the mechanical properties of CR/BR blends with carbon black additives. As a result, it is thought that the rubber composition containing 50 phr HAF N330 carbon black will be suitable for the composite material to be used as vibration damper in rail systems.