Curing characteristics, tear, fatigue, and aging properties of bentonite‐filled ethylene‐propylene‐diene (EPDM) rubber composites

Abstract

This article investigates how the presence of bentonite clay in ethylene‐propylene‐diene (EPDM) composite affects curing characteristics, tear strength, fatigue, and aging properties. The process of compounding of EPDM/Bt composite was carried out by two‐roll mills and the compound was compressed into sheets at 150°C. Monsanto Disc Rheometer was used to determine the curing characteristics, whereas its tear strength was measured by Instron machine. The aging of EPDM/Bt composite was carried out by putting the samples into a 100°C oven for 48 h. Meanwhile, the fatigue strength of the EPDM/Bt composite was measured through Fatigue To Failure Test machine. Results indicate that the curing time (t 90 ) and minimum torque (ML) of EPDM/Bt composite increases with every increase in Bt loading. The scorch time (t s2 ) increases only after 30 phr was added in EPDM/Bt composite and it continue to rise until 90 phr Bt. Meanwhile, maximum torque (MH) increases with Bt loading and decreases after 90 phr of Bt was added. Tear properties of EPDM/Bt composite have found to be increased with Bt up to 90 phr. The resistance of EPDM/Bt composite toward aging also increases but up to 70 phr of Bt and this can be seen in the increased percentage of retention in EPDM/Bt composite. Fatigue life, however, decreases with increases in Bt loading. Morphological study carried out through scanning electron microscope suggests that there is a buildup of agglomeration when excessive amount of Bt is added into EPDM/Bt composite. This addition leads to the poor properties of EPDM/Bt composites. J. VINYL ADDIT. TECHNOL., 24:E77–E84, 2018. © 2017 Society of Plastics Engineers