Human Hair Modification By Stretching

Along with the raise of living standard of the people and the change of consumption sense, the market demand of wigs is becoming more and more. Though wigs made of chemical fiber have many advantages, the hygroscopicity, permeability and flame retardance of wigs made of human hair is far better than that of wigs made of chemical fiber due to human hair belongs to natural fiber, people with them will not feel stuffy and dry, therefore, wigs made of human hair are the first selection'of people. This tendency promotes the improvement of bleaching and dyeing technology of human hair. However, the chlorination pretreatment of existing bleaching technology of black human hair may produce absorbable organic halogen compounds (AOX). Hence, the chlorination technology is being restricted by environmental legislation and faced with the pressure of being banned finally. In addition, wigs made of chlorination-bleaching technology are not resistant to ultraviolet and become aged easily, so their service life is short and the market demands their qualities to be improved further. Consequently, researching and developing a new bleaching technology of black human hair which is beneficial to environmental protection and the end product is durable has become the exertive aim of the textile research workers as well as wig manufacturers. Another problem that wig manufactures confront is that, owing to Chinese origin hair fibers are coarser, wigs made of them are harsh to the touch and it is difficult to meet the new and higher demands of customers.The main aim of this thesis is to develop a new bleaching technology of human hair that is environmental protective and to make wigs of the best quality. Testing results show that a few tiny-crazes appeared on the cuticle of the fiber after hair fibers were stretched, subsequently, it was advantageous for bleaching reagents to enter into human hair fibers and act on natural coloring matter, as a result, human hair could be bleached effectively. On the other hand, after stretching-setting treatment, the length of human hair increased and its fineness reduced, hence, human hair with better fineness and more comfortable handling can be obtained. Stretching treatment of human hair is mainly a physical modification process and it doesnot involve the matter of environmental pollution, it has a bright applicable future.Strength and extension properties after modification treatment of human hair by stretching are one of the emphases of this thesis. Human hair is a -keratin fiber, physical and chemical treatment will cause fiber damage, making its mechanical property worse off. It was found that during the stretching梥etting treatment of human hair, stretching protectant of wool and hair had an obvious protective function on human hair fiber, it could block part of sulfhydryl groups generated in the reaction, and hinder them from rebuilding disulf ide bond and other resemble cross-linking randomly. So being in existence of stretching protectant of wool and hair, after stretching treatment alone(non-setting), breaking strength increases first and then declines with increasing extensions breaking extension tends to increase and the toughness becomes better, and the discrete coefficient reduces; on the other hand, after stretching梥etting treatment of human hair, breaking strength of fiber declines slightly, while breaking tenacity increase and breaking extension only declines slightly comparing with that of untreated hair. Therefore, stretching protectant of wool and hair is the key guarantee for this modification technology by stretching of hair fiber.Another focal point in this thesis is to study the bleaching and dyeing performance of human hair and wool after modification by stretching. After stretching treatment of black human hair, good bleaching results can be achieved without chlorination treatment. The cuticle of end product made of the new bleaching technology of human hair by stretching梥etting treatment is intact on the whole, it still has good protective function on human hair, and...