A novel strategy to prepare rubber/clay nanocomposites via compounding clay gel into cocoamidopropyl betaine modified styrene butadiene rubber

In this study, high performance styrene-butadiene rubber (SBR)/clay nanocomposites (NCs) modified by cocoamidopropyl betaine (CAPB) are prepared via an efficient and facile strategy. CAPB-modified SBR was compounded with clay gel via gel compounding method to obtain SBR/clay composites. The effect of processing condition and CAPB on the mechanical properties of the SBR/clay composites was investigated. XRD and TEM results show that clay dispersion in SBR matrix is significantly improved due to the success of CAPB in the hydrophilic modification of SBR. The clay-SBR interaction is enhanced and more SBR molecular chains are adsorbed to the clay, significantly improving the mechanical properties of SBR/CAPB/clay NCs, as demonstrated by SEM and DMA. The maximum tensile strength of SBR/CAPB/clay NCs achieved 16.3 MPa at a clay loading of 40 phr, which is 10 times that of pure SBR. The tensile strength of the SBR/CAPB/clay NC incorporated with 20 phr clay has exceeded that of the SBR composite incorporated with 40 phr commercial organic clay. This work demonstrates that this strategy, which combines the CAPB-modification of SBR with the gel compounding method, is an effective and feasible method to improve the mechanical strength of SBR.