The masterbatch of unsaturated polyester (UP)/nano-silver obtained by using the Unidrive X1000 CAT mixer at 14000 rpm in 50 mins. The field emission scanning electron micrograph showed the flock of nano-silver has burst into smaller clusters and dispersed evenly in PU. The viscosity of matrix resin containing different nano-silver contents was almost unchanged except 100 ppm. Moreover, the presence of nano-silver has prolonged the gel and curing time but increased maximum exothermal temperature of emission. In general, the presence of nano-silver improved strongly in mechanical properties of composite especially nano-silver content of 60 ppm. Two bacterial strains: gram-positive bacterial (S.aureus) and gram-negative bacterial (E.coli) were used to evaluate the antibacterial property of sample. The results showed matrix resin without nano-silver possessed antibacterial property with both strains. The presence of nano-silver raised the gram-positive antibacterial property but reduced gram-negative antibacterial property of matrix resin.
