Investigations of antibacterial activity of chitosan in the polymeric composite coatings

•Antibacterial behaviour of chitosan in the polymer composite was investigated.•Composites were produced by adding chitosan as powder and colloid state to acrylic resin with different loading level.•Zone of inhibition on the nutrient agar plates were estimated, and percent decreasing tests were performed.•A comparison was done between solid and colloid chitosan effectiveness.•Colloid chitosan demonstrated much better antimicrobial activity in the composites than powder. Chitosan and its derivatives can be called environment purification functional materials that they can effectively control the growth, reproduction of hazardous bacteria and also control toxic pollutants. In this study, an acrylic resin was converted to an antibacterial composite material by using chitosan. Different states of chitosan; solid state (powders) and colloid state, were inserted to the polymer matrix individually. Glass substrates were coated with this polymeric matrix. Obtained samples were characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM) and scratch test. Antibacterial activity against Staphylococcus aureus (S. Aureus) was studied by applying entitled in vitro test. Zones of inhibition were estimated on the nutrient agar plates, and also percent decreasing tests were performed. It was concluded that chitosan can be considered an effective antibacterial additive. Colloid chitosan reinforced composites demonstrated much better antimicrobial activity comparing with powder chitosan reinforced ones.