Investigation of the properties of mesoporous silicon dioxide (SiO2) filled ethylene propylene diene monomer (EPDM) rubber

The purpose of this study is to find out how mesoporous silicon dioxide (SiO2) affects the mechanical, thermal, electrical and rheological properties of EPDM rubber. Using 1.5 lt of laboratory-type mini banbury and open shafts, the SiO2 particles at 5, 11, and 22 phr (per hundred of rubber) ratios were prepared, following production prescriptions. Subsequently, test plates were obtained by vulcanizing at 180° for 20 or 40 minutes. The rheological and fluidity properties of the EPDM rubber were studied with pre-press motion mold rheometry (MDR) and Mooney viscosity tests. There were tensile tests and permanent deformation tests to determine post-vulcanization properties, density and Shore A hardness tests to determine physical characteristics, and dispersion analysis for the distribution of additives existing in EPDM rubber. It was found that the mooney viscosity values and optimal cure times (T90) increased, but the curing rate index (CRI), cure extent (CE), and maximum torque (MH) decreased compared to EPDM rubber samples that had no additives added. Increasing the amount of additives led to a slight increase in the samples' hardness values, which ranged from 58 to 63 Shore A. As the amount of mesoporous SiO2 increased, so did the density and ash content. In EPDM/22MSiO2 rubber samples, the ash content increased by 135% and the density also increased by 4.1% compared to EPDM rubber samples. When mesoporous SiO2 was added to EPDM rubber, the breaking strength and tensile module values (M100, M200, and M300) increased and then decreased, and the breaking elongation values decreased and then increased. An increase of 3.8% and a decrease of 35.4% in breaking strength values were observed, and breaking elongation values ranging from 497% to 655% were detected.