Effect of zinc dimethacrylate concentrations on properties of emulsion styrene butadiene rubber/butadiene rubber blends

The influence of zinc dimethacrylate (ZDMA) on the properties of emulsion styrene butadiene rubber/butadiene rubber (ESBR/BR) blends was studied. Results revealed that torque difference, hardness, strengths, and total/ionic crosslink densities increased; whereas the elongation at break and covalent crosslink density reduced with increasing ZDMA. As ZDMA increased, the ionic crosslink density of the blends gradually increased. Optimum tensile and tear strength of the compound were observed at 12.5 phr of ZDMA. At 5 and 7.5 phr of ZDMA, the blends showed significant good healing efficiency, supported by the characterization tests such as scanning electron microscopy (SEM) and manual video measuring machine (VMM). Fourier-transform infrared spectroscopy (FTIR) analysis showed the presence of ZDMA in the blends. The dynamic ionic bond of ZDMA contributed to the self-healing properties in the blends. The zinc ions pair constituted the ion multiplet and ionic clusters, forming an ionic supramolecular network.