Surface modification of polyester film by comamonas testosteroni

Polyester film has been widely applied in engineering plastics field, but the high hydrophobicity and low surface free energy limits its usage and desires its surface modification. Biomodification of materials is a developing field which can improve the surface property of materials whithout environmental pollution and high energy consumption. Comamonas testosteroni which could biodegrade the monomer of polyester film diethyl terephthalate was used to biomodify polyester film. The modification reaction was carried out in constant temperature oscillator for 15 days. Diethyl terephthalate was added into the modification medium termly as inducing substrate to induce the microbe secrete more enzymes to catalyse the modification of polyester film. The surface property of the original and modified polyester film were tested through contact angle examination, XPS analysis and FTIR. The results showed that hydrophilicity and surface free energy of the film was increased; the content of oxygen element in the molecules increased; a small quantity of phenolic hydroxyl group appeared on the surface of the film; lipase catalysed hydrolysis reactions and oxygenase catalysed oxidation reactions might occur at the surface of the film according to the degradation pathway of the simulacrum diethyl terephthalate.