Effect of electron beam irradiation and degree of boric acid loading on the properties of styrene-butadiene rubber

Synthetic and totally amorphous styrene-butadiene rubber (SBR) has been loaded with varying contents of boric acid. Vulcanization of prepared composites as well as of unloaded rubber has been induced by ionizing radiation of accelerated electron beam of varying doses up to 250 kGy. Evaluation of prepared composite subjected to this range of irradiation has been followed up through the measurement of mechanical, physical, electrical and thermal properties of vulcanized composites. Mechanical properties, namely tensile strength (TS) and Young's modulus were found to increase, whereas elongation at break (Eb) and permanent set (PS) were found to decrease with the increase in degree of boric acid loading as well as irradiation dose. On the other hand, physical properties, namely the gel content, have increased whereas the swelling number has decreased. Moreover, increase in the decomposition temperature has been attained. Also, limited increase in electrical conductivity has taken place. Data obtained indicate enhancement in thermal as well as in physico-mechanical properties of prepared composites. Moreover, 60 phr of boric acid has attained good mechanical properties.