COMPARISON OF THE PROPERTIES OF TREAD RUBBER FOR WHOLE WITH METAL CORD HEAVY-DUTY TIRES BASED ON NR AND ON SYNTHETIC POLYISOPRENE SKI-3 OF VARIOUS BRANDS

Technological properties of rubber compounds as well as viscous-elastic and strength properties of the tread rubber for heavy-duty tires whole with metal cord (MCT), based on blends of natural (NR) or synthetic polyisoprene of various trade marks (more than 80 %) and polybutadiene (more than 10 %) were studied. The new processing aid (PA), worked out in LLC «NPP QUALITET» under registered trade mark KVALISTROL® A100, was suggested instead of importing analogous of PA Polyplastol 6 type. It was established that replacement of NR in MCT formulation by the SKI-3S rubber produced with the use of a new anti-agglomerator of a crumb of KVANTISLIP® of the BM-2R, PA A100 brand, increased dosage of sulfur-accelerated group and the corrected dosage of the vulcanization inhibiter Santogard PVI and together with the worked out mixing mode at a stage of production of masterbatch allows to receive rubber compound close to reference on the basis of the NR on viscosity. At the same time the new rubber compound's strength and elastic properties practically don't differ, and in the lowered values of a hysteresis, surpass reference rubber compound with NR use.

Enhanced Tribological Properties of Vulcanized Natural Rubber Composites by Applications of Carbon Nanotube: A Molecular Dynamics Study

Tribological properties of tread rubber is a key problem for the safety and durability of large aircraft tires. So, new molecular models of carbon nanotube (CNT) reinforced vulcanized natural rubber (VNR) composites have been developed to study the enhanced tribological properties and reveal the reinforced mechanism. Firstly, the dynamic process of the CNT agglomeration is discussed from the perspectives of fractional free volume (FFV) and binding energy. Then, a combined explanation of mechanical and interfacial properties is given to reveal the CNT-reinforced mechanism of the coefficient of friction (COF). Results indicate that the bulk, shear and Young’s modulus increase with the increasement of CNT, which are increasement of 19.13%, 21.11% and 26.89% in 15 wt.% CNT/VNR composite compared to VNR; the predicted results are consistent with the existing experimental conclusions, which can be used to reveal the CNT-reinforced mechanism of the rubber materials at atomic scale. It can also guide the design of rubber material prescription for aircraft tire. The molecular dynamics study provides a theoretical basis for the design and preparation of high wear resistance of tread rubber materials.

Investigation of the elastic and hysteresis properties of tread rubber tires with silica

The influence of different types of silica, differing in quality characteristics, on the complex modulus of rubbers, their elastic modulus, loss modulus, and also on the tangent of angle of mechanical loss are investigated. Mineral fillers silica 1 and silica 2 are introduced at a dosage of 80.00 phr into filled elastomeric compositions based on combination of synthetic styrene-butadiene and polybutadiene rubbers, used for the manufacture of treads for passenger tires. The tests are carried out on a dynamic mechanical analyzer by cyclic compression of vulcanizates in the temperature range 20–70°С. It is established that vulcanizates with silica 2 are characterized by 8–56% lower value of the complex modulus. It is revealed that rubbers containing a silica 2, depending on temperature, have 13–36% lower values of the elastic modulus and 19–46% lower values of the loss modulus in comparison with samples filled with silica 2. It is determined that in the temperature range from 20 to 70°C vulcanizates with silica 2 are characterized by 7–12% lower values of the tangent of angle of mechanical loss. As a result of the study, it is established that it is the most expedient to introduce mineral filler silica 2 into the formulation of tread rubber compounds for passenger tires. This will make it possible to obtain vulcanizates with increased elasticity and adhesion to the road surface, as well as lower heat losses to the environment and fuel consumption.