The Research On Degumming Technique Of Hemp Fibers By UV-Freezing-Heating-Microwave Alkaline Cooking

As a natural fiber, hemp fibers possess superior hygroscopicity, breathability, comfortableness, heat dissipation and antibacterial properties, and could be blended with cotton, wool and silk. As higher gum content brings negative influence to hemp fiber, it is necessary to develop degumming technology to improve its quality and spinnability. At present alkaline cooking degumming method is commonly used in industry. As a chemical degumming strategy, it caused high energy and water consumption, let alone the alkali liquor discharge.The paper narrates a new technology suitable for the degumming of hemp UV-Freezing-Heating-Microwave alkaline cooking (UVFHM) technology. In this article a novel degumming technology including pre-impregnation, UV-Freezing-Heating and microwave alkaline cooking was developed and employed in the degumming of hemp fibers, and enhanced degumming efficiency was achieved with lower energy and alkali liquor consumption. A new UV-Freezing-Heating-Microwave alkaline cooking technology was developed and applied to hemp degumming. The effects of UV-radiation, Freezing-Heating and Microwave alkaline cooking on residual gum content were discussed. The morphology and structural changes of hemp fibers before and after degumming were characterized by Scanning electron microscopy (SEM) and Fourier transformed infrared spectrum (FT-IR). The results indicated that part of gum was first removed and coarse surface was produced after UV-radiation. Then the Freezing-Heating treatment facilitated the removal of the large pieces of gum. After the microwave alkaline cooking step, most of gum was removed from the surface of hemp fibers. As a result the lower residual gum content of2.70%and residual lignin of0.75%were obtained under UV-radiation, Freezing-Heating and Microwave alkaline cooking.