Investigation of Composition and Processing Parameters on the Mechanical Properties of Magadiite/SBR Composites

摘要

This work investigates mechanical reinforcement and energy dissipation in styrene-butadiene rubber (SBR) composites containing sulfur-functional, organosilane-modified magadiite (MGD), a layered silicate (Na2Si_(14)O_(29)·9H2O). MGD has plate-like active filler particles with surface chemistry similar to precipitated silica. Previous research demonstrated that MGD/SBR elastomers have better mechanical properties than silica/SBR composites with the same filler weight loading. MGD has significantly higher specific surface area than silica, and both the SI-69 coupling agent and SBR can access the MGD interlayer space, resulting in superior reinforcement. This work aims for a deeper understanding of reinforcement mechanisms in MGD/SBR composites by investigating more deeply the influence of composition and processing parameters on composite mechanical properties. We treat MGD with cetyl trimethyl ammonium (CTA), dodecyl pyridinium (DP) and hexadecyl ammonium (HDA) cations to produce "organo-MGD" materials with varying initial interlayer spacing. Using these materials, we explore the hypothesis that larger organo-MGD spacing will permit greater access of SBR into the MGD interlayer gaps. We prepare cross-linked MGD/SBR samples with varying organo-MGD materials, varying levels of SI-69 addition, and varying mixing time to study the influence of those factors on mechanical reinforcement. All samples are characterized by XRD after mixing, milling, and curing steps to help us understand at what stage SBR enters the MGD interlayer. DMA and tensile testing quantify the mechanical properties. This work will help us better understand the impact of non-spherical filler particle shape on reinforcement mechanisms and energy dissipation in platelet-filled elastomers.