Flax Fiber Dyeing Performance Improvements

The dyeability of the flax fiber can be improved provided the flax fiber is chemically modified by the urea solution under the microwave treatment, which has been studied in detail in this paper.Theoretical analyze and repeating experiments have been done firstly. The results have showed that the flax fiber treated by the urea solution under the microwave treatment had significantly improved dyeability. The procedure of modification to the flax fiber has been optimized. And the procedure of dyeing the flax fiber through pad-dyeing and bath-dyeing also has been optimized.Based on the analysis of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscope (XPS) to the flax fiber, it could be significantly seen that the amino group (NH2) was introduced to the flax fiber. That the activity of amino group (NH2) was much more higher than that of hydroxyl (OH) resulted in the increased reaction probability between the dye molecules and the flax fibers. Therefore, the dyeability of the flax fiber modified by the urea solution under the microwave treatment had been greatly improved.Based on the analysis of scanning electron microscopy (SEM) and X-ray diffraction (XRD) to the flax fiber, it was considered that the roughness of the surface of the flax fiber has been increased and the fiber bundle has significantly become swelled, which was successfully benifical to the adsorption of the dye molecules by the flax fibers during pad-dyeing and bath-dyeing and the diffusion of the dye molecule into the flax fiber. As a result, the probability of the reaction between the dye molecule and the flax fiber increased, resulting in improved color depth and dye exhaustion of the dyed flax fiber.The modification procedure could be applied in the industrial scale flax dyeing with satisfactory level of exhaustion and fixation, and have the advantages of green environmental protection, low consumption of energy and mature technology.