Free Radicals in Cellulose Fibers Treated with Low Temperature Plasma

Abstract

Cellulose fibers such as cotton, linen, viscose rayon, and polynosic fibers were treated with low temperature plasmas of O2, N2, H2, Ar, CO, CH4, and CF4. For comparison wool, silk, nylon 6, and poly ( ethylene terephthalate ) (PET) were also subjected to the plasma treatments. The relative free-radical intensity of the plasma-treated fibers was measured by means of ESR spectroscopy. The free radicals in the fibers treated in the plasmas increased in the following order: cotton > wool > silk > nylon 6 ≃ PET. cotton > linen > mercerized cotton > polynosic fibers ≃ viscose rayon, and CF4 > CO > H2 > Ar > CH4 > N2 ≃ O2. The natural fibers, in particular cotton and linen, showed larger free-radical intensity than the regenerated cellulose and the synthetic fibers. The free-radical intensity of the plasma-treated fibers depended considerably on the plasma characteristics and the fine structure of the fibers as well as their chemical constitution.