Bast fibre degumming

Hemp processing with microwave and ultrasonic treatments, was the topic of the paper presented to the 83rd World Conference of the Textile Institute, Shanghai, held in May 2004. For the study, microwave process was conducted on two typical varieties of hemp. Microwave heating was applied to non-retted hemp under alkaline condition to degrade non-cellulosic substances. It was observed that the mean fiber width of the degummed hemp was significantly reduced after the microwave process. The results of the treatment combinations further show that the effects of the ultrasonic treatment depend on the use of microwave treatment in processing. By increasing the treatment time the fiber lightness can be further increased. In addition, the effects of ultrasonic treatment very much depend on the use of microwave treatment in that it can facilitate the ultrasonic treatment to separate the fibers properly and remove color pigments effectively.