Preparation and investigation of mechanical and antibacterial properties of poly(ethylene terephthalate)/chitosan blend

Abstract

The aim of this work was to evaluate the anti-bacterial and mechanical properties of chitosan based solvent-cast blends with synthetic poly(ethylene terephthalate) (PET). The amount of chitosan loading was varied from 1% to 9% (w/w). Chitosan and PET were homogeneously dissolved in a ternary solvent system with different mass ratios in a trifluoroacetic acid, chloroform, and acetic acid solution and processed into uniform films. Molecular interactions between chitosan and PET were investigated using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. Morphology and tensile properties of these blend films were investigated. The antibacterial activity of the samples was evaluated utilizing the colony forming unit method against three typical human pathogenic microorganisms, Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus. The results indicated that the PET/chitosan films showed a significantly higher growth inhibition rate compared with the PET film. Chitosan release from a wide range of blends was studied using the ninhydrin method. The release tests revealed that dissolution of the biocide glucosamine groups, i.e. the chitosan water soluble fractions, also increased with the increase in the amount of chitosan content. Results obtained from ATR-FTIR spectra suggested that there exist pronounced interactions that probably resulted from hydrogen bond formation between different components. SEM micrographs showed that the compatibility of the two polymers was reduced when the fraction of chitosan was increased. Tensile strength and elongation at break of the blends reduced with the increase in chitosan content. These results indicated that the blends became brittle upon increasing the chitosan content.