Studying On Degumming Process And Research Of Structure And Properties Of Cotton Stalk Bast Fiber

As people think highly of natural fibers and exploit them ,the hidden resources of cotton stalk bark have gradually been paid attention to , and the development and utilization of cotton bast fiber have become one of the hot spots in the field of textile. Cotton Bast fibers not only pioneered the development and utilization of new approaches to the use of cotton stalk, but also adds a new type of natural fiber,which is significant. Therefor, this paper conducted the following research work aims to extract the cotton stalk bark fiber by bio-degumming process and study the fiber properties.By analysising the chemical composition of cotton stalk bark, the quantities are measured. The content of cotton stalk bark fiber is 41.05%,which is relatively slightly lower than hemp fiber,and the quantity of lingnin and pectin is 15.83% and 9.86% respectively, and the content of resin is higher than that of hemp fiber.Technical process was confirmed by making hemp bio-retting process for reference and making the comprehensive assessment of enzymatic degumming effect.That is pretreatment→pre-pectinase degumming→hot water washing→cold water washing→→weak acid handling of water washing→play fibers→dilute alkali treatment→cold water washing→play fibers→white-rot bacteria delignification→hot water washing→cold water washing→weak acid handling→water washing→drying. And semi-degumming method was used for cotton bast fiber.In this paper, single-factor test, orthogonal experimental design are used to determine the scope of the study, and also by analysising the factors that affect the degumming effect and validation tests to determine the optimal level of parameters which are as follows:in the pre-treatment: H2SO4 4g/L, Temperature: 70℃, time : 2h, bath ratio: 1:15;and in enzyme treatment: enzyme dosage: 5 g / l; Temperature: 40℃; pH value: 4.5; time: 10h. white-rot bacteria dosage: 0.9g/L, Temperature: 36℃: time:7 day, bath ratio: 1:15. By observing in SEM ,the cross section of the cotton stalk fiber is found to be oval-shaped with cavity, therefor it is a natural hollow fiber;the vertical section of the fiber has grooves,and the surface is uneven. The length of the longest cotton bast fiber which is prepared by the optimum process is 280.7mm,and the shortest is 6mm,the average is 75.6mm, the length dispersion is large, it ranges from 20 to 160mm.The average linear density is 16.5tex, the irregularity of the fiber is 11.1%,and it's breaking strength is 23.74cN/tex.All of the references above can meet the requirement of spinning.Through the bio-degumming ,the residual lignin is still high,which may be related to the removal effect of white-rot fung.And the high residual lignin makes the softness of the fiber do not have a substantial increasement,which can't meet the needs of spinning process.The standard regain of the cotton bast fiber is 8.56%.In this paper, thermal gravimetric analysis is used to have a brief analysis of the thermal properties of the cotton bast fiber.And also the fiber has good moisture permeability.So cotton bast fibers have a certain prospect.Through the reseach, cotton stalk bast fibers as a new type of textile natural resources have similar or even better performance than hemp fibers,which make they have a much greater development and utiliaztion value.However, bio-degumming process received a high rate of residual lignin fibers, which will affect their spinning, dyeing and finishing performances and limit the development prospects.