Degumming of thai silk by low-pressure plasma treatment

Abstract

Degumming of Thai silk was completed by using low pressure plasma with glow discharge. The plasma treatment was operated at discharge powers of 60, 250, 1000, and 2000 W. with exposure time varied at 5, 10, and 15 min, at oxygen flow rates of 250, 500. and 1000 cc/min, and chamber temperatures of 25, 50, and 75 ℃ Weight loss and mechanical properties were measured to evaluate the efficiency of the degumming process compared to a conventional degumming. as well as scanning electron microscopy (SEM). staining method with direct dye, and x-ray diffraction (XRD). The optimal plasma treatment for raw Thai silk fiber was at 2000 W, 10 min exposure time, oxygen gas flow rate of 500 cc/min, with the chamber operated at 25 ℃. Conventional degumming could remove sericin by 24.05±l.06 % while the optimized condition of the plasma treatment was 9.17±0.29 %. The breaking strength of the conventional degummed silk was 5.523±0.197 and elongation was 21.90±1.10, while those of the plasma treated silks were 6.719±0.309 and 23.00±l.60, respectively. Color strength of the raw silk was 2.85. whereas the conventional degummed silk was 0.07 and the plasma treated silk was 1.74. The XRD of the plasma treated silk showed higher crystallinity. Unlike the conventional method, the plasma treatment had the ability to remove only the external surface of raw silk with less penetrating power than the conventional solution. However, the plasma treatment has advantages in terms of being a cleaner, more environmentally friendly technique, and achievment of lower operation time than that of conventional degumming.