Production of safe and antimicrobial ethylene propylene diene monomer (EPDM) rubber vulcanizates for toys and medical applications

Abstract

The present work deals to prepare safety rubber goods for medical and kids toys applications. The rubber used in this study was ethylene propylene diene monomer (EPDM). The incorporated additives used to obtain promising results for safety rubber goods are ZnO of particle size 26 nm, potassium alum and tetracycline. Two fillers were used like CaCO3 and bentonite. The rubber and its specified ingredients were mixed through the ordinary industrial mixer applied. The compounded rubber was vulcanized by a hydraulic press according to the time determined from the rheological test. The physico-mechanical properties and the cytotoxicity tests of the EPDM rubber vulcanizates were evaluated. The results showed that rheological properties of the vulcanizates depend on the type of filler; CaCO3 and bentonite used. The scorch time decreased with increasing filler concentrations. The minimum and maximum torque as well as the cure rate index were increased with increasing the filler concentration. The data obtained showed the improvement of the physicomechanical properties of the vulcanizates in presence of 10-20 phr fillers . Moreover, there is no great differences in the rheological and physicomechanical properties of the prepared vulcanizates in the presence of the bioactive materials such as ZnO, potassium alum, and tetracycline due to their good compatibility and distribution of these materials in the vulcanizates as clarified from the results of the scanning electron microscope (SEM). The results of cytotoxicity test on the prepared vulcanizates towards human normal cell lines showed good safety property therefore, the cytotoxicity activity of EPDM/Bentonite at 100 ppm was about -58.5 %, while, the antimicrobial activity of EPDM/Bentonite/2.5 ZnO towards Gram -ve or Gram +ve bacteria was good. These promising results push us to use EPDM rubber vulcanizates for producing safe and antimicrobial rubber goods in various industrial and medical applications.