Surface modification of PET film and fabric by oligo-chitosan treatment

Poly(ethylene terephthalate) (PET) films, comprising surfaces hydrolyzed with caustic soda solution to incorporate the functional groups of carboxylic acids, were treated with a solution containing chitosan oligomer, a cross-linking agent, and a catalyst in order to modify various surface characteristics, including hydrophilicity and anti-staticity. Chitosan oligomers were prepared by depolymerizing chitosan with sodium nitrite. The chitosan molecules were fixed to the PET film surface by the reaction between the carboxylic groups in the PET film and the amino groups of the chitosan molecules. FT-IR(ATR) spectra, surface free energies, anti-staticity and other properties were measured and interpreted in relation to the structural change that was induced in the PET films by these treatments. In addition, we investigated the effect of chitosan oligomer treatment on the handle of polyester fabrics by using Kawabata evaluation system. The hydrophilic and anti-static properties of the PET film were highly improved by alkaline hydrolysis and low-molecular-weight chitosan treatment. The handle of PET fabric was gradually hardened by chitosan treatment with increasing the concentration of chitosan.