Chitosan coated cotton fiber: preparation and physical properties

A new cotton fiber with a chitosan coating (CCCF) was prepared by the oxidation of a cotton thread with potassium periodate at 60°C in water and subsequent treatment with a solution of chitosan in aqueous acetic acid. Infrared spectra of the CCCF suggested the formation of Schiffʹs base between the chitosan and the oxidized cellulose. Kjeldahl nitrogen analysis of the CCCF showed that the maximum percentage of chitosan introduced into the cotton fiber was 1.58% (w/w). Treatment of the fiber with 2ʹ,7ʹdifluoro fluorescein (an amino group-specific probe) followed by fluorescent microscopic analysis revealed that the modification with chitosan occurred on the surface of the cotton fiber. Scanning electron microscopy (SEM) photographs showed that the surface of the CCCF was slightly changed after the series reaction. However, the mechanical strength of the cotton thread, which was oxidized by the potassium periodide solution at a concentration of less than 2.0 mg/ml, was found to be almost the same as the original cotton thread. Furthermore, a model experiment for the controlled release of the drug was preformed using shikonin, a component of a Chinese medicine, suggested potential usefulness of the CCCF as a supporter for the controlled release of drugs.