Preparation and characterization of antibacterial chitosan/Ag–montmorillonite with improved dynamic mechanic properties

Chitosan/Ag–montmorillonite (CS/Ag–MMT) nanocomposite was obtained via solution intercalation. The X-ray diffraction and transmission electron microscopy results indicated the successful formation of intercalated-and-exfoliated nanostructures at low Ag–MMT contents and intercalated-and-flocculated nanostructures at high Ag–MMT contents. The CS/Ag–MMT nanocomposite with 7 wt% Ag–MMT presented a very high inhibition ratio against Staphylococcus aureus (>70%), and its bacterial inhibition zone diameter was 3.2 mm larger than that of CS, which showed remarkable antibacterial activity. When the Ag–MMT content was 5 wt%, the E′ of CS/Ag–MMT was increased to 3,261 MPa, which was 195% higher than CS and exhibited excellent mechanic property. The DMA test results showed the Tg of CS/Ag–MMT shifted to a higher temperature, suggesting the Ag–MMT interlayer not only interacted quite strongly with the reactive groups of CS but also restricted the motion of CS macromolecules, which was also verified by Fourier transform infrared spectrum measurements. POLYM. COMPOS., 35:1980–1988, 2014. © 2014 Society of Plastics Engineers