Thesis (M.Sc.)--Chulalongkorn University, 2007

In this study, effect of carbon black type and content to the electrical property and physical properties of Neoprene rubber as well as aging time at 125°C were studied. High conductivity, low viscosity and long aging time were achieved in the rubber compound containing carbon black with high structure (high DPE), low surface area (low BET) and low critical volume fraction, c even though small amount was added to the rubber compound. These properties of rubber compounds are advantageous for the molding and processing. The rubber compound with CCB0075CB shows the optimum value of conductivity. The change in conductivity of the rubber compound was obviously observed when carbon black content was in the range of 20 to 35 phr. Physical property after aging at 125°C of the rubber compounds filled with CCB0075 at 20 and 30 phr was studied. The density, hardness, tensile strength and conductivity of the rubber compound increased with aging time until day 30-35th and constancy afterward. The result is due to the lost of small volatile molecule from polymer matrix and the carbon black particles are more close to each other. The rubber compound filled with high carbon black loading could be degraded easier than that filled with low loading. The result in this study can be useful in the production of conductive rubber as well as the prediction of their degradation.