Papers by Keyword: Rubber Composite

Abstract: Wear resistance is an important rubber compound property related to useful product life. The rubber compound properties that affect wear behavior are very complicated. Wear is related to a rubber compound’s cut resistance, tear resistance, fatigue resistance hardness, etc. The most commonly used test method to determine the wear resistance of rubber materials is abrasion test. Tested compounds are usually compared on a “volume loss” basis which is calculated from the weight loss and density of the compound. This method is known to be variable and doesn’t give additional information for the wear behavior. For this reason we propose alternative approaches for examination of the wear behavior of rubber composites, giving information not only for the wear resistance but also for elastic the modulus, stiffness of the material, damage mechanism, etc. Continuous multi-cycle indentation is used to determine the indentation hardness, elastic modulus and the stiffness with two indenter types –Vickers and sphero-conical. Comparison of both results is made in order to investigate the effect of the indenter type.

Abstract: Thermal conducting silicone rubber composites filled with aligned nickel (Ni) nanoparticles induced by magnetic field were prepared by the solution mixing process. The structure, thermal, dielectric and magnetic properties of the silicone rubber composites were investigated by optical microscopy, laser flash thermal diffusivity analyzer, LCR digital meter and vibrating sample magnetometer. The results show that with the induction of magnetic field, Ni nanoparticles aligned form thermal conducting networks resulting in increase of the thermal diffusivity and relative dielectric constant of the silicone rubber composites.

Abstract: This paper presents a numerical model of rubber composite using a COMSOL multiphysics program to simulate electrical properties of the rubber composite in the frequency range of 300 kHz to 30 MHz. The rubber composite was made of natural rubber vulcanized with carbon black and carbon nanotube. The chracterization was done by setting up a parallel plate capacitive structure in a shape of circular disk with a diameter of 38 mm and using the RF vector network analyzer to measure electrical properties in term of electrical impedance, specifically resistance (R) and reactance (X). Three different thinknesses of rubber composite sheets were used in the experiment, specifically 0.7 mm, 1.7 mm, and 2.9 mm. From the physical dimension of the test setup, capacitance (C), dissipation factor (D), relative permitivity (ε_r), and conductivity (σ) can be calculated. These extracted parameters together with the physical dimension of the test structure were used to create COMSOL multiphysics simulation models. The program can simulate non-linear modeling of the rubber composite under different electromagnetic constrains. The simulation results were compared to the measured results for all samples. Comparison results show that all electrical parameters were closly matched, indicating that the COMSOL multiphysics models were correctly generated. The results also indicate that the conductivity and the relative permittivity of the tested rubber composite change dramatically at the frequency above 10 MHz. The results indicate the physical limit of the tested rubber composite in the sensing application. The simulation model proposed in this paper can be used to design and possibly predict the geometical and electrical properties of the rubber composite in future applications.

Abstract: During rubber processing, many factors can affect the mechanical properties of rubber composite. The influence of ambient temperature and content of titanate coupling agent and modified attapulgite (OAT) on mechanical properties were investigated by preparing rubber composites and measuring. The results showed that the rubber composite which was filled 40phr OAT modified by 3% titanate and prepared at the ambient temperature above 20 had best tensile strength (18.93MPa). There is a special phenomenon that the tensile strength had a rapid increase from 4.72MPa to 18.93MPa, when the content of OAT changed from 20 to 40phr in the experiment.