Studies On The Yunjin No.1 Cotton And Its Spinnability

As the common raw materials, the need of Sea Island cotton is improved quickly with the future boost to demand of high quality textiles. Since Sea Island cotton could only be cultivated in the special environment, the cotton has been confined to the area of Northwest in China. However, the researches to transplanting Sea Island cotton to other place haven't been interrupted, but at present there is no breakthrough.Through the method of gene crossing and inducing, according to characteristics both of Sea Island cotton in Xinjiang and Upland cotton, a medium long staple upland cotton which has characteristics of Sea Island, Yunjin No.1 cotton has been successfully cultivated. Not only the cotton fiber has excellent quality, but also has both high yield and the ecological adaptability which adapts to be planted in the Southern China. It could effectively reduce transport cost and enlarge planting area, the most important is that it would improve both quantity and quality, create added value. For the new medium long staple upland cotton, the systematic theory and study were scarce in the structure and properties, therefore few products development were based on those, either.The basic on those mainly in this paper, first, such as the morphological, the fine structure, physical and mechanical properties and so on, at the same time, the relationship between structure, properties and spinnability of Yunjin No.1 cotton were discussed. Then the seed coat neps, effective length, short-staple rate and combing waste noil of semi-finished products in the preparatory spinning were studied. The effects of properties of Yunjin No.1 cotton on the fineness, strength, hairiness and so on were discussed also. At last, the mechanical properties before and after treated by caustic soda solution and the wicking properties of Yunjin No.1 yarn were studied. From the above discussion, the structure and properties of Yunjin No.1 cotton and yarn were studied systematically and comprehensively. The conclusions were as follows:1 Yunjin No.1 cotton is purity cellulosicⅠfiber; orientation degree is about 68%. Comparing with the gossipier barbadense from Xinjiang, it has medium maturity, more natural convolution, shorter length, higher short-staple rate, slightly more coarse fineness. For the properties, it has lower breaking tenacity, higher breaking elongation rate, more rigid, excellent electroconductivity properties, less arger static and dynamic friction coefficient, less cohesion.2 The degree of crystallinity is higher and higher as picking extension. As later picked-period, the breaking tenacity and breaking elongation rate of Yunjin No.1 cotton are higher, but moisture absorption is worse.3 The thermal cracking of Yunjin No.1 cotton started from almost 300℃, and the main phase is from 300℃to 460℃, the weight decrease sharply and rise more than 90%. By the increase of concentration of caustic soda solution, the cross section of cotton fiber was changed from kidney-shape to ellipse gradually.4 The seed coat neps and short-staple rate of Yunjin No.1 cotton lap increase then gradually reduce, but the change of effective length is on the contrary.5 For the structure of yarn, the hairiness of Yunjin No.1 yarn is shorter than that of Upland cotton yarn. The evenness in short term is more uniform, moreover, its evenness in long term is the same as Upland cotton yarn and Upland cotton/Sea Island cotton blended yarn. The weight per 100m of Yunjin No.1 cotton yarn are slight lighter, however, the number of neps are more than 140neps/g.6 Both of the breaking tenacity and initial elastic modulus of Yunjin No.1 cotton yarn are higher than that of Upland cotton yarn, but the breaking elongation rate is lower. Yunjin No.1 cotton yarn is rigid, the elastic recovery rate is 50%, moreover, compact yarn is higher. The changes of stress during the stress relaxation process were simulated and analyzed by the standard linear Models, related equations were set up. The experimental data agree with the theory values during the stress relaxation phase. The stress relaxation phenomenon of Yunjin No.1 cotton yarn isn't obvious. Both of the breaking tenacity and breaking elongation rate increase after treated by caustic soda solution, but the initial elastic modulus reduce and the alkali resistance is better than that of Upland cotton yarn. The wicking equilibrium height of Yunjin No.1 yarn reaches more than 8cm.