One of the most important problems in the production of polymer composites that subject to the environmental pollution is making them antibacterial. Preparation of antibacterial polypropylene (PP) according to their extensive uses in food packaging industries, medical instruments, cloths and etc is very important. In this study, chitosan and silver were used for preparation of antibacterial polypropylene composite. For chitosan immobilization, utilized a melt mixing grafting to active PP, followed by grafting with acrylic acid (AA) and then coupling with chitosan molecules by using of N-(3-Dimethylamnopropyle)-N'-ethylcarbodiimide (EDC) as a coupling agent. Results showed the degree of immobilization of chitosan on PP increased with graft ratio of AA on PP. The samples were characterized by FTIR spectroscopy. In the FTIR of PP-g-AA samples which contained the chitosan, the new absorption peaks at about 1570 and 1634 cm -1 (CO-NH) were appeared. A silver- polypropylene nanocomposite was produced from solution of silver nitrate that contained of polypropylene powder, in the presence of ethylene glycol as a reduction agent by sonochemical method. Poly(vinyl pyrrolidone) (PVP) with different molecular weight (M w ) was used for preventing the agglomeration of silver nanoparticle. The results indicated by increasing the concentration of AgNo 3 in the working solution and reaction temperature, the size of immobilized silver was increased. By controlling the reaction condition and use of ethanol instead of water as dispersed solution of silver in working solution, fine dispersion of silver nanoparticle on the surface of PP in the one percent concentration was achieved. The investigation of different MW of PVP was appeared that the size of nano-particles was decreased with increase of M w of PVP. The XRD patterns of deposited Ag nanoparticles on the PP demonstrated that the silver is crystalline, and Ag nanoparticles with an average size of ? 24 and 7 nm were deposited on to the PP and PP-g-AA respectively. The IR spectrum obtained from PP-g-AA suggested that embedding of silver on PP-g-AA accomplished by ion exchanged process between H + and Ag + . Also the SEM images revealed a fine dispersion of silver particles in PP and PP-g-AA. According to results of silver ion release from samples, the existence of acrylic acid polar groups on PP and quenching of PP/Ag composite after molding improved the condition of silver ion release from the PP matrix.The antibacterial property of polypropylene which containing nanosilver and chitosan was evaluated according to ASTM E2149. It was proved that the polypropylene composite which containing nanosilver and chitosan had an excellent antibacterial property. Furthermore, by increasing in silver release from polypropylene matrix the antibacterial ability of
