Desenvolvimento de uma formulação elastomérica de EPDM para aplicação em temperaturas elevadas.

Abstract

The objective of this work was to obtain an EPDM elastomeric formulation for application at high temperatures. The influence of characteristics such as the ethene, propene, and diene content and Mooney viscosity, the use of stabilizers and different curing systems, and the variation of the filler and plasticizer content on the morphology and physico-mechanical and dynamical properties of the formulations were evaluated. Based on a standard formulation for application at high temperatures, the use of an elastomer of higher Mooney viscosity showed the best properties of minimum and maximum torque, tensile strength, and compression set. The formulations prepared with stabilizers showed no improvement in the resistance to thermal aging based on the evaluation of the compression set performed at 70 °C and 120 ° C. Comparing the curing systems, the formulation cured through the efficient system presented the best set of results, including thermal aging resistance, compared to other compositions cured through the semi-efficient system or peroxide. The enhancement of the properties was due to a greater predominance of monosulfidic crosslinks which are thermally more stable than the disulfidic and polysulfidic ones. Finally, the formulation with a reduced content of filler and plasticizer presented best balance of properties, with an increase in the retention of properties with the thermal aging and lower compression set. These are the main characteristics of interest for the proposed application.