effect of the tires crumb rubber loading levels on nr/sbr compounding properties for antibacterial applications

In this study, the reuse of tires crumb rubber (tcr) has been studied by adding it to natural rubber/styrene butadiene rubber (nr/sbr) compounds with many loading levels such as (15,20,25,30 phr), as well as adding the 40 phr from haf-n.330 to nr/sbr for comparison. tcr is cheap and helps the formation of porous rubber compounds, which help to absorb more amounts from bacteria solution and increase wettability by reducing the contact angles. many tests were carried out to obtain the required specifications, such as processing properties, crosslink density, and surface morphology, such as scanning electron microscopy (sem) images, contact angles, mechanical properties, and compression set. results proved that increasing tcr levels in nr/sbr compounds leads to a reduction in cure rate index (cri), tensile strength, the difference in torque (∆h), and crosslink density by 35.1 %, 45.74 %, 68.4 %, and 38.46 %, respectively. ft-ir spectra proved the high and strong bond appearance at the control sample (without tcr) and weak interaction at 30 phr of tcr. in addition, the sem micrograph images show the porous rubber surface at 25 and 30 phr, which allows for the absorption of more amounts of bacteria solution and the leaching of zinc oxide nanoparticles to the surface, then attacks bacteria. therefore the 30 phr in compound (e) had a high inhibition zone against s. aureus 2cm and against e. coli 1 cm compared with an inhibition zone of the control sample without tcr 0.5 cm against s. aureus and no activity against e. coli.