Optimization and effect of 3‐aminopropyltriethoxysilane content on the properties of bentonite‐filled ethylene propylene diene monomer composites

Abstract The effect of silane coupling agent, 3‐aminopropyltriethoxysilane (APTES) content on the curing, tensile, swelling, and morphological properties of bentonite (Bt)‐filled ethylene‐propylene‐diene monomer (EPDM) composite was studied. The EPDM composites containing constant Bt composition of 30 phr and various APTES content (0, 1, 3, and 5 phr) were prepared using a laboratory scale two‐roll mill. The result showed that the cure time ( t ₉₀ ) and scorch time ( t _S2 ) were shortened, whilst, the cure rate index (CRI), the maximum ( M _H ) and minimum ( M _L ) torque increased with increasing APTES content. The experimental results revealed that the optimum APTES content that led to the highest tensile and swelling properties was 3 phr. The presence of APTES greatly improved the dispersion of Bt in EPDM matrix and enhanced the interfacial interaction between EPDM and Bt. Morphological study through scanning electron microscopy revealed the enhanced adhesion between EPDM and Bt in the presence of 3 phr APTES. POLYM. COMPOS., 33:1993–2000, 2012. © 2012 Society of Plastics Engineers