Preparation of modified rectorite powder and structure and properties of modified rectorite powder/rubber composites

The aminosilane coupling agent KH550 modified rectorite(REC) powder was prepared by the spray drying method, and the influence of the inlet air temperature on the surface characteristics, structure and morphology of the modified REC powder was examined. The modified REC/ styrene-butadiene rubber(SBR), REC/natural rubber(NR) and REC/nitrile-butadiene rubber(NBR) composites were prepared by the melt blending method. The dispersion of the modified REC powder in the rubber matrixes and its reinforcement effects on the matrixes were also investigated. The results show that raising the inlet air temperature increases the amount of KH550 in the modified REC, and then promotes the modification of REC. KH550 molecules intercalate into the intergallery of REC, resulting in smaller aggregates and more loosely packed structures in the modified REC powders. No intercalation of rubber macromolecules into the interlayer of REC occurs in all three modified REC/rubber composites. The modified REC layers aggregate locally in SBR, they are uniformly dispersed in NBR, and exhibit the best dispersion state in NR. Compared with the corresponding the pure rubbers, the mechanical properties of the modified REC powder filled SBR and NBR composites are comprehensively improved, regarding the modified REC/NR composite, the stress is enhanced, the tensile and tear strengths are kept unchanged, and the elongation at break is decreased compared with the pure NR.