چكيده به لاتين
Today, mineral clays, especially montmorillonite nanoparticles (MMT), have gained special importance due to their unique properties. Many studies have shown that the addition of MMT to rubber matrices, as a polymer, is very widely used and increases physical-mechanical properties. In order for a nanoparticle to perform properly, it is necessary to use its maximum specific surface capacity which is created in nano the materials nano dimention. For this purpose, if a nanoparticle is layered, these layers must be separated. In this project, exfoliation of MMT nanoparticles was done by dissolving of MMT in the water solvent and using ultrasound waves and its success was confirmed by XRD, FTIR, and FE-SEM analyzes. However, MMT has a tendency to create cluster and this causes not to achieve uniform distribution in the matrix. In this research, surface modification of MMT was achieved by two methods: washing with sodium hydroxide and with the help of silane coupling agent (trimethoxyvinylsilane). Also, the effect of the concentration of silane agents in the aqueous solution during the surface modification reaction was evaluated. Finally, the performance of natural rubber/styrene butadiene rubber (NR/SBR) nanocomposites without nanoparticles, containing raw MMT, exfoliated MMT and modified silanized MMT was compared. NR/SBR-MMT nanocomposites were investigated by tensile tests, rheology tests and DMTA, RPA and FE-SEM analyses. The results showed that the silane groups were successfully attached to the MMT surface. The optimal curing time for the composite containing exfoliated and silanized nanoparticles decreased by 32 seconds and 56 seconds, respectively, compared to pure NR/SBR. The 100% modulus and 300% modulus for the sample containing exfoliated nanoparticle has increased by 7% and 3%, respectively, and for the sample containing nanoparticle modified with silane, has increased by 103% and 20%, respectively, compared to pure NR/SBR. Elongation at break increased by 12% and decreased by 7% for the sample containing exfoliated and silanized nanoparticles compared to pure NR/SBR. Also, the storage modulus of the nanocomposite containing silanized MMT increased by 54% compared to pure NR/SBR, and the glass transition temperature also increased by 7 degrees for the nanocomposite containing silanized MMT.
