Research On Cashmere Stretching Slenderization Processing And Mechanism

Cashmere fiber is a rare and expensive special animal fiber. But as the character ofitself, such as the short length, over crimped and high depth crimp, it brings trouble tothe real manufacture. If it can be put some kind of action such as stretching oncashmere fiber, the fiber length can be longer, the crimp status can be improved andalso the fiber fine can be smaller. The fiber after stretching modification is not only infavor of the processing behind, but also it can use the cashmere resource adequatelyand upgrade value of the cashmere resource.Cashmere fiber and wool fiber are mostly the same, and wool slenderization bystretching technology is well developed. This study is based on wool slenderizationby stretching technology to research on the processing and mechanism of cashmerefiber slenderization. But cashmere and wool fiber exist little difference after all, soeach condition suited to the wool slenderization may not suit to the cashmereslenderization and which should be chosen again.Cashmere slenderization processing by stretching includes the pretreat processingbefore stretching and each parameter value when stretching. Cashmere slenderizationby stretching pretreat liquid is chosen follow the patent. Pretreat processing (factor)before stretching mainly includes the concentration and temperature of the liquid andthe dipping time. And the factors above also have the level themselves, this study usethe orthogonal experimental design to choose the level of each factor. The judgementstandard of experiment is through taking the single fiber from the pretreated cashmereto do the single fiber stretching test, and at last base on the break strength,breakelongation and stretching stress rate to decide the level of each factor.After the pretreat liquid treated processing, and then stretch the cashmere throughthe stretching machine, the slenderized cashmere fiber can be obtained. It also shouldmake certain the stretching parameters' value such as the twist of the cashmere,holding gap and stretching velocity and so on. When making certain the twist of thecashmere, it is twisted different twist to the cashmere, and then stretch the cashmerein different stretching rate and stretching velocity and so get the stretching curve.Compare each curve, and base on the principle of lowest stress and longest yield areato make certain the optimal twist of cashmere. And it is in the same way when makingcertain the holding gap and stretching velocity. Base the parameters certained, it istested the utmost stretching rate and the optimal stretching rate of the cashmere whichpretreated in the optimal pretreating condition.This study also test the performance of the slenderized cashmere, including thefiber's fine, length, crimp, squama, friction performance and shrinkage rate in boiledwater. From the test result, it is found that some of the performance of the slenderized cashmere's are descended, but some performance which are related to the process anduse of the cashmere such as length, crimp and fine are upgraded in different degree.These upgrades are the aims of cashmere fiber slenderization modification. But it alsoneeds to decrease the performance damage to the fiber in greatest effort.When researching the mechanism of the cashmere slenderizing, this study analysesthe transformation of a-helix chain toβ-pleated sheet from the infrared spectrum,cross section TEM photograph of fiber slice and X-ray crystallinity both before andafter stretching the fiber. From the experiment result, it is found that in the fiberstretched exists the transformation of a-helix chain toβ-pleated sheet. But thetransformation of a-helix chain toβ-pleated sheet can only be in qualitative not inquantitative. This study also takes the theory that the mechanism of the cashmereslenderizing is the transformation of a-helix chain toβ-pleated sheet in the course ofstretching and making theβ-pleated sheet fixed which is the same mechanism withwool stretching slenderization.LiLiming(Textile materials＆Textile Design)Supervised by Processor Yu Weidong＆Liu Hongling...