Surface modification of fibrillar silicate and its reinforcing mechanism on FS/rubber composites

In this paper, the remarkable effect of surface modification of fibrillar silicate (FS) on the mechanical properties of FS/rubber composites was explored. The mechanism of surface modification and reinforcing mechanism of FS were also discussed. It was found that types and amounts of silane coupling agent significantly affect on mechanical properties of FS/rubber composites. By the analysis of IR and NMR, it was indicated that the alkoxyls at one end of silane coupling agent could react with the hydroxyls on the surface of FS to form Si–O–Si bond. And meanwhile the organic functional group at the other end of silane coupling agent could tangle or react with macromolecules. Interestingly, the dispersion of FS and the FS–rubber interfacial bonding were significantly affected by the modification methods, especially what kind of and how much silane coupling agents were used in the modification. Modified FS with Si69 was found out with extraordinary reinforcing effects for SBR, EPDM, NBR and CNBR. According to the observations of TEM and SEM, most of modified FS could be separated into nano-size fibrillar dispersing units under mechanical shear.