The role of ion-exchange bentonites in changing the properties of styrene–butadiene rubber composites

Natural bentonite containing Na and Ca was cationically exchanged with Ba, Sr, Cu and Cu–Ba. These different Ion exchange bentonites (IEBs) were used as fillers in styrene–butadiene rubber composites. Different loadings of IEBs were incorporated in SBR matrix to study their effect as reinforcing filler. A comparison was held out between different loadings and the different cations in IEBs on the SBR properties. The rheometric characteristics, physico-mechanical properties and swelling were determined. The study revealed that the performances of Ba- and Sr-bentonites are the best among the group with an optimum loading at 15 phr. Cu bentonite show the least performance, while addition of Cu to Ba deteriorate the reinforcing efficiency of Ba.

► Bentonite containing Na and Ca was exchanged with Ba, Cu, Sr and Ba-Cu.
► Ion exchanged bentonites were incorporated in styrene–butadiene rubber.
► Rubber containing Ba and Sr bentonites show better mechanical properties.
► The optimum loadings of Ba and Sr IEBs were 15 phr, and was only 5 phr for Cu and Cu–Ba-bentonites.