Effect of low-temperature oxygen plasma on the degumming of ramie fabric

Abstract

Ramie fiber is one of the most important materials for textile manufacturing. However, the conventional degumming processes for ramie involve numerous chemicals and water consumptions, resulting in a serious environmental concern. The purpose of this work is to investigate the effect of low-temperature oxygen plasma (LTP-O2) treatment on ramie fabric degumming in combination with a subsequent mild wet chemical process. The oxygen plasma treatment variables such as oxygen gas pressure, discharge power and exposure time were investigated and optimized according to the indexes of fabric total impurity removal, whiteness, capillary rise height, tensile strength and elongation, etc. The results show that a notable effect of oxygen plasma on ramie degumming was observed in a subsequent mild wet chemical process. The fabric capillary rise height, whiteness, tensile strength and elongation of the pretreated ramie were improved with gas pressures from 20 Pa to 40 Pa, although accompying with a decrease tendency in impurity removal, as well as for the capillary rise height as pressures higher than 40 Pa. Furthermore, the fabric impurity removal, capillary rise height were enhanced with plasma discharge power from 30.0 W to 250.0 W, with less affects on fabric whiteness, tensile strength and elongation. Moreover, most of the degumming indexes were also improved as the exposure time from 1.0 min to 3.0 min, except for a worse deterioration of fabric tensile strength as an exposure time longer than 5.0 min. An optimized plasma process for ramie fabric degumming was at 40.0 Pa of oxygen gas and 250.0 W of glow discharge for 3.0 min. In comparison with a control and conventional degumming processes, higher degumming effects and mechanical properties of ramie fabric were achieved by the combination degumming process with more environmentally friendly due to less consumption of chemicals, water and energy. Moreover, the effect of oxygen plasma on ramie fiber was further confirmed and characterized by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM).