Nanocompósitos de borracha natural e nanotubos de carbono dispersos em látex para preparação de elastômeros com alta condutividade elétrica

Abstract

Thanks to rapid technological advancement, especially in the electronics industry, new trends and needs are emerging. In this sense, metallic materials traditionally used for these applications that require high conductivity are becoming increasingly less attractive as they are expensive, heavy, difficult to process, and oxidize and their extraction is harmful to the environment. Thus, conductive polymer composites (CPC), more precisely conductive elastomeric composites (CRC) of natural rubber (BN) and carbon nanotubes (CNT) have attracted the attention of researchers thanks to their combination of elastic and electrical properties. Thus, in this work, the effects of CNT concentration on the mechanical and electrical properties of nanocomposites with BN cured with dicumyl peroxide (DCP) were evaluated. The nanocharges were dispersed using sonication in latex. The ideal concentration of DCP was also evaluated. Samples with three different concentrations of DCP were analyzed using torque rheometry. Nanocomposite samples were prepared with three different concentrations of nanotubes and the selected concentration of dicumyl peroxide. One of the samples was duplicated, but without the use of two stages of ultrasonic sonication to evaluate the effectiveness of the sonication stages. These samples were pressed and subjected to tensile and hardness tests to evaluate the mechanical properties, while impedance spectroscopy (EIS) was used to measure the electrical properties. The theory of equivalent electrical circuits (CEE) was used in conjunction with EIS to evaluate electrical parameters in greater detail. From the results, the electrical properties and mechanical properties were obtained, which increase as the concentration of CNT increases. Strain at break was the only mechanical property that reduced with increasing nanofiller percentage. The electrical properties of the sample with one less sonication step increased, but much less than that of the sample of equivalent concentration that went through all the steps, indicating that the sonication steps are very important for the dispersion of nano charges and affect directly electrical conductivity.