Development of novel functional conducting elastomer blends containing butyl rubber and low-density polyethylene for current switching, temperature sensor, and EMI shielding effectiveness applications

A new class of functional conductive butyl rubber (IIR) with different loadings of low-density polyethylene (PE) was prepared by roll mixing in a milling at a rotor speed of 24 rpm. To understand the filler dispersion and filler/matrix interaction, the network structure of the specimens was examined by evaluating of the crosslinking density, volume fraction of elastomer, interparticle distance among conductive phases, interfacial area per unit volume, torque rheometer, hardness, tensile strength, elongation at break, X-ray, glass transition temperature, thermal gravemetry, differential scanning calorimetry, degree of crystallinitv, and SEM microanalysis. Static conductivity, mobility carrier's concentration, number of charge carriers, and thermoelectric power as a function of PE content were investigated. The temperature dependence of the electrical conductivitv as well as the conduction mechanism of IlR-PE blends were also analyzed. The isothermal resistance stability test was examined by displaying the resistance-time curve at certain temperatures. Them relationship between current and DC applied voltage was measured for all samples. The self-electrical heater with PE content of 10 wt % exhibited the highest nonlinearity. The thermal stability was tested by means of temperature-time curve at certain applied power, on and off, for two cycles. Dielectric constant and relative loss factor of the blends are reported. The applicability of the rubber system for switching current, temperature sensor, and electromagnetic shielding effectiveness (EMT) was examined. The experimental results of EMT were compared with theoretical predictions. The results of the present study indicate that these blends are suitable for switching current, temperature-sensitive sensor, and EMT shielding effectiveness applications with good thermal stability for consumer products. (c) 2005 Wiley Periodicals, Inc.