Studying On Moisture Transmission Through Bast Fabrics With Liquid Ammonia Treatment

In this thesis, bast fabrics including hemp, flax and ramie were treated by liquid ammonia treatment. Morphological structure, crystal structure and chemical composition of bast fibers were tested by use of scanning electron microscope, X-ray diffraction tester and infrared micro-Raman spectrometer. Wetting properties of bast fabrics such as air permeability, vapor permeability, radiation capability, moisture adsorption and liberation, wicking ability, moisture conductivity, water inhibition, drying performance and liquid moisture dynamic management properties were also tested. The relationship between wetting behaviors and fiber structures was discussed. Furthermore, the fuzzy comprehensive evaluation was adopted to obtain the quantitative comprehensive evaluation results of moisture transmission through the bast fabrics with liquid ammonia treatment. The results showed that after liquid ammonia treatment, the structure of bast fabrics was tighter and the quantity of yarn hairiness was less; the streak and the fissure were reduced or vanished obviously on the surface of fibers which were smoother and rounder; the X-ray crystallinity decreased and the lattice form converted from celluloseâ… to celluloseâ…¢while there has been little change on chemical composition; the radiation capability, moisture adsorption and liberation ability, wicking ability and water inhibition of bast fabrics were poorer, but they were better in air permeability, vapor permeability, moisture conductivity and drying performance; the MMT indexes of liquid moisture dynamic management properties of ramie fabric were all improved, however, water absorption rate and spreading speed of hemp and flax fabrics decreased while their wetting time, accumulative one-way transport capacity and overall moisture management capability were improved; the fuzzy comprehensive evaluation results showed that the bast fabrics including hemp, flax and ramie had better moisture transmission after liquid ammonia treatment. To some extent, wetting properties of bast fabrics were greatly influenced by the change of their morphological and crystal structures after liquid ammonia treatment.