| Ramie and flax woven fabrics have many unique advantages. They have excellent properties including good moisture absorption and dispersibility, good air permeability and heat transport. Its strength is high with little static electricity. It is not easy to be polluted and appropriates to human skin's excreting. Its ultraviolet shield and bacterium restraint functions are identified by national authorized organization. In textile industries, the softer ramie and flax fabrics are more often used than other bast fibers. But ramie and flax fabric's elasticity are weak and the wrinkle and abrasion resistance are poor. These disadvantages have restricted the development of ramie and flax fabric for a long time.Hydroenhancement process is a new fabric treatment technology developed from the mid-1990s. Its principle is that the woven or knit fabrics are exposed under the water jets by screen or roller and either one side or both sides of the fabrics are impinged by high pressure water stream. Having reached the desired degree of treatment, the texture and structure of the fabricscan change. The performance in every aspect, such as the abrasion and pilling resistance can also be improved significantly. The thickness can be increased and the surface becomes denser. The air permeability can be either increased or decreased depending on the change of fabric structure. The uniformity of the fabric over the width improves.At present, hydroenhancement process has been used in pure or blended fabrics made of cotton, polyester, nylon, polypropylene, acrylic, etc, and good results have been achieved. It also has been applied successfully in home textiles, automobile sector, garment fabrics and filtration fabrics. However, there are no documents found yet that provide explanation to the change of fabric's performance after hydroenhancement. By now this process has not been experimented in ramie or flax fabrics. If, after hydroenhancement, ramie and flax fabric can be retained their advantages and their disadvantages can be improved like poor elasticity, the ultimate products must have broad market.This dissertation shows an attempt to apply hydroenhancement to ramie and flax woven fabrics in order to improve the bast woven fabrics with an economic and convenient physical treatment. It begins with designing the process parameters by pioneer experiments, then through observing thechange of fabric's texture and performance, analyses the treatment effect by different water pressures, different treatment times and different treatment direction, gives the explanation. The conclusions are as follow:1. Hydroenhancement experiment parameterWater pressure can be adjusted to 60 bar, 65 bar, 70 bar, 75 bar, 80 bar, 90 bar.Treatment times can be adjusted to 1 time, 2 times, 3 times, 4 times.The direction of treatment can be adjusted to warp direction and weft direction.The velocity of transport can be adjusted to 2 m/min and 2.5 m/min.2. After hydroenhancement, the follow effects can be observed:(1) The fabric structure becomes dense, the warp and weft yarns spread uniformly.(2) The fabric side last moved underneath the water jet is smooth and clean, the side last on the transporting element has a velvet appearance.(3) Tha fabric becomes stiffer and coarser, the luster declines obviously.(4) The fabric's aperture diminish, and the thickness, gram per square meter, warp and weft density of the fabric rise.(5) The fabrc's break strength changes, break elongation and break work rise, correspondingly, the abrasion and pilling resistance also rise.(6) The fabric's wicking effect improves, while air permeability and vapor permeability reduce, and wrinkle resistance declines.3. The elements influencing the hydroenhancement result are as folows:(1) If the transport velocity and treatment times are constant, the higher the water pressure is, the intenser the hydroenhancement is.(2) If the water pressure and treatment times are constant, the lower the transport velocity is, the intenser the hydroenhancement is.(3) If the water pressure and transport velocity are constant, the more the treantment times is, the intenser the hydroenhancement is.(4) The finer the yarn is, the more obviously the strength of the fabric after hydroenhancement declines. If the yarn twist is less, the fabric's strength will increase after hydroenhancement. Ifits density is less, the fabric will shrink more severely, corresponding appearance are fabric's thickness, gram per square meter, density and strength all increase.Zhuang Meini (Textile Engineering) Supervised by Associate Professor Zhuang Qinliang...
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