Papers by Keyword: Rubber

Abstract: The article investigates the effect of vulcanizing systems of different activity on the vulcanization and elastic-strength properties of rubber compounds based on ethylene-propylene rubber Keltan . Were taken vulcanizing systems: a mixture of organic peroxide, sulfur and sulfenamide accelerator (1); a mixture of organic peroxide, sulfur and dithiodimorpholine (2); a mixture of organic peroxide, sulfur and thiuram accelerator (3); sulfur and sulfenamide accelerator (4). The vulcanization characteristics (maximum and minimum torques; times of onset, optimum and reaching the maximum speed of vulcanization) were evaluated. Elastic-strength (conditional tensile strength, elongation at break, hardness) properties of rubber compounds and operational (changes in conditional tensile strength, elongation at break after aging in air) were determined. It was found that the vulcanizing system (3) containing sulfur, peroxide in an amount of 7.0 parts by weight and thiuram accelerator imparts the best elastic and strength properties to rubber compounds and leads to their resistance to high temperatures.

Abstract: Damping properties are crucial in determining the dynamic structural response. In this paper, the experimental results for Neoprene rubber of 40, 50 and 60 shore A hardness are reported in view of improving structural damping to control noise and vibrations. Additionally, the system loss factors of the unconstrained layer damped structures of same material were predicted by Ross-Kerwin-Ungar equation to validate the obtained experimental results. The results showed that Neoprene rubber (also known as Polychloroprene) of 60 shore A showed better static and dynamic characteristics than those of the 40 and 50 shore A hardness. The system loss factor results reached the saturation when the applied viscoelastic layer thickness was increased from 40 mm to 50 mm in unconstrained damping. As such, the proposed method can help to build a database of the properties of various materials which are applicable in the design of noise and vibration control.

Abstract: The effect of modified silica fume (mSF) and cellulose fiber (CF) content on the cure characteristics, mooney viscosity, mechanical, durability and heat resistance properties are investigated; as compared with SF and unfilled natural rubber. From the results reveal that mSF and CF affect not only fast cure rate, high viscosity but also improve rubber mechanical and heat resistance properties. Additionally, the mSF and CF are added into the natural rubber to produce antivibration rubber product and then study the rubber product performance such as durability properties. The mSF and CF effective in improving the crack resistance of antivibration rubber product more than SF and unfilled natural rubber which is due to enhancing the stiffness. The all obtained results, it can be proved that mSF and CF as the new alternative fillers in rubber industry.

Abstract: Advanced developed technologies associated with people demands have caused production and expansion of different local wastes where the process of managing such waste becomes a real need for controlling the pollution risk. One of the procedures for recycling can be made through using local wastes in permeability control for sandy soil since the soil permeability plays a crucial function on the water drainage, pore water pressure buildup and dissipation, and ground movement for saturated sand during and after earthquake occurrences. In addition, any economical mixture should maintain hydraulic constraints for practice use. In this study, a laboratory experiment was prepared to perform tests for estimating the water movements and permeability in a pure sand column and treated sandy soil with different locally waste materials including plastic, glass, rubber, and aluminum. In addition, a numerical investigation including finite element method has been adopted to verify the experimental procedure. It was shown that the permeability could be controlled to different rates using these local wastes.

Abstract: This paper deals with an FEM simulation of a steel belt of tyres. A belt is a part of a tyre that plays a very important role in all radial tyres especially in case of heavy-duty off-the-road (OTR) ones. It is a composite composed of rubber material and a steel reinforcement. High peak stress inside this composite can initiate cracks, which subsequently lead to a complete tyre failure. In this work, the belt is extracted from the tyre and simulated separately in order to be able to cover individual cords. Belt behaviour under tension is studied and optimal cord distribution is proposed to decrease the risk of the failure. FEM software MSC Marc/Mentat is employed as a calculation tool.

Abstract: One of the ways to improve the qualities of asphalt and concrete mixes is to modify the binding agent in its composition with polymer additives. The article presents rubber with polyethylene and vinyl acetate (sevilen) as a modifying additive to the road construction bitumen. The impact of rubber on the properties of the polymer bitumen binding agent (PBBA) was analysed. The mode of action of the complex additive was explained, the evidence-based concentration of rubber in PBBA was identified.

Abstract: Conventional road materials used for producing wearing courses of roads are based on mineral aggregate and bituminous or Portland cement binders. The road materials must be optimized for different properties, including skid resistance, durability, rolling resistance and tire/road noise. Unfortunately, it seems that within classic technologies it is very difficult to achieve further reduction of tire/road noise. Innovative porous material PERS that contains considerable amount of crumb rubber seems to have great potential of traffic noise reduction. The paper presents brief history of PERS development, its present stage and unexpected properties, for example, spill fuel fires retardation.

Abstract: This article focuses on the Finite Element (FE) analysis of the ballistic performance of the polymer composites consisting of natural rubber (NR), glass-epoxy (GE) and glass-rubber-epoxy (GRE) sandwich of different thicknesses (3, 6 and 9 mm) under the impact of the conical nose projectile for a velocity variation of (180, 220 and 260 m / s). FE modeling was carried out in direction to forecast the energy absorption, ballistic limit velocity and failure damage mode of the target materail. The significant influence of thickness, interlayer and sandwiching effect was studied: the lowest ballistic limit was obtained for 3 mm thick GE. Energy absorption capacity of GRE sandwich was highest among the natural rubber and GE. In future, the work can be extended for the experimental validation purpose, so that these polymer composite materials could be utilized to defence sector for bullet-proofing.

Abstract: The chopped aramid fiber reinforced rubber composite (AFRC) has been widely used in the tire treads for its excellent characteristics. The viscoelasticity which is an important mechanical property for rubber matrix would be influenced by the adding of aramid fiber. In this study, the dynamic and quasi-static viscoelasticity were investigated via the dynamic thermal analysis experiment and the mullins experiment with multi-step relaxation, respectively. The frequency and temperature scanning were employed for AFRC with different fiber volume fractions, fiber aspect ratios and fiber orientation distributions. The effects of constituent parameters on the dynamic viscoelasticity were studied as well as the general rule of reinforcing effect of aramid fiber on rubber materials was presented. The stress relaxtion for AFRC were analysed basing on the experimental results. In addition, The ability of the viscoelastic constitutive model to describe the quasi-static viscoelastic behavior of AFRC were explored.

Abstract: The processes of pyrolysis and combustion of rubber-based synthetic rubbers were studied. Determined that Teflon (polytetrafluoroethylene) helps reduce the rate of burning rubber in half, from 0.25 mm/s to 0.14 m/s based on a mixture of isoprene and butadiene-styrene rubbers