The effect of bentonite loading on the curing, tensile and morphological properties of Ethylene-Propylene-Diene Monomer (EPDM) composites

Curing behaviour, tensile and morphological properties of bentonite (Bt) filled Ethylene-Propylene-Diene Monomer (EPDM) composites at various Bt loading were investigated. EPDM/Bt composites were prepared using a laboratory size two-roll mill by adding 0 to 70 part per hundred rubber (phr) of Bt. Curing time (t90) and scorch time (tS2) were reduced initially with 0 to 30 phr Bt loading and increased subsequently at 50 and 70 phr. Results obtained showed that tensile strength and elongation at break of EPDM/Bt composites were increased with incorporation of 0 to 50 phr Bt and decreased at 70 phr Bt loading, whereas the tensile modulus at 100% elongation (M100) showed an increasing trend with increasing Bt loading from 0 to 70 phr. Scanning Electron Microscope (SEM) was used to examine the morphology of tensile fractured surface which revealed the good interaction between Bt particles and EPDM to an optimum Bt loading of 50 phr and agglomeration of Bt particles at 70 phr.