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Nanosilver colloid, Ag-based zeolite compound, and 2-hydroxypropyl-3-piperazinylquinolinecarboxylic acid methacrylate (HPQCAM) were used as antimicrobial agents and/or mechanical property improvers in peroxide-cured silicone rubber vulcanizates. The vulcanizates were prepared by using a two-roll mill followed by a hydraulic press in order to vulcanize the rubber compounds, and their cure characteristics, mechanical properties, and antibacterial performance were assessed. The antimicrobial performance of the silicone rubber compounds was examined through plate-count-agar and drop-plate-agar methods, as well as the halo test. The results suggested that the addition of all of the antimicrobial agents slightly increased the cure time, except for the Ag-based zeolite. The addition of all of the antimicrobial agents also affected the mechanical properties of the rubber vulcanizates. The Ag-based zeolite gave the silicone rubber compound with the most improved mechanical properties, whereas HPQCAM was the most effective antimicrobial agent, as determined by the occurrence of the inhibition zone and 99% reductions of Staphylococcus aureus and Escherichia coli. The changes in silicone rubber surface with the addition of antibacterial agent were shown by progressive decreases in water contact angle. This result was observed only for the HPQCAM agent and was associated with diffusion and the releasing mechanism of the HPQCAM to kill the bacteria. The optical lightness of the silicone vulcanizates decreased with increasing nanosilver content but increased with increasing amounts of Ag-based zeolite or HPQCAM. J. VINYL ADDIT. TECHNOL., 19:113–122, 2013. © 2013 Society of Plastics Engineers