Enhancement of the thermal and physicochemical properties of styrene butadiene rubber composite foam using nanoparticle fillers and electron beam radiation

This study investigates the physicochemical and thermal properties of styrene–butadiene rubber (SBR) nanocomposite foam. Nano-calcium carbonate (CaCO${}_3$) was prepared from eggshells (ESs) waste. Sponge rubber nanocomposites were prepared and were irradiated by electron beam (EB) radiation at 25, 75, and 150 kGy. Their physicochemical properties, including foam density, compression set (CS), hardness, abrasion loss, and expansion ratio, and their thermal stability were investigated. The physicochemical properties were enhanced by adding 2.5 phr of a foaming agent. Among the composites examined, the foam composites containing nano-CaCO${}_3$ had the lowest CS, abrasion loss, and expansion ratio and the highest hardness and foam density. The results confirmed that the thermal stability was improved by incorporating nano-CaCO${}_3$ into the SBR foam and as the radiation dose increased. The sponge containing nanoclay demonstrated an intermediate behavior, whereas that with CaCO${}_3$ nanoparticles showed low average cell diameter and size and high cell wall thickness. The radiation process enhanced the foam density, CS, abrasion loss, hardness, and thermal property of the developed nanocomposites by inducing the formation of intermolecular crosslinks within the composite matrix. The results showed that physicochemical properties improved by increasing the radiation dose at 25 kGy.