Visualization And Composition Analysis Of Flax Roving Microstructure And Optimization Of Enzymatic Degumming Process

Flax fiber has high application value and is often used as textile material or renewable composite reinforced material.Flax fiber is obtained from roving degumming.Traditional chemical degumming not only has great pollution and high cost of sewage treatment,but also has great damage to the fiber.As a result,the strength of flax fiber after degumming is not enough to meet the requirements of advanced fiber raw materials.It is urgent to develop green manufacturing technologies such as biological degumming to realize the technological upgrading of the industry.At the same time,because flax fiber is a short fiber,it needs to rely on gum adhesion to form technical fiber.Therefore,the degumming degree is very important.If the degumming degree is too large,the fiber is easy to break,while if it is too small,the fiber is difficult to disperse,which is not conducive to subsequent spinning.Studies have shown that there are weaknesses in flax roving that are easy to break-"dislocations".However,there is still a lack of research on how to control the degree of flax degumming to prevent the fracture of the dislocation.Therefore,based on the comparative analysis of the structure and composition of dislocations in flax roving,this study optimized the enzymatic degumming process of flax roving to obtain highquality flax fiber with less damage at the dislocations.The main findings obtained are as follows:(1)Based on the microscopic visualization method,the surface and internal structural features of flax roving dislocations were studied and classified,and the effects of different degumming enzymes were further analyzed.The dislocations on flax roving can be divided into four types: links,nodes,kinks and knots.The outer layers of the four types of dislocations all have gum wrapping,which covers up the uneven and discontinuous defects of the flax roving itself.It was found that pectin was mainly wrapped in the outer layer of dislocations,and hemicellulose was the main component of the chemical composition of the dislocation;and dislocations were easily damaged during degumming,resulting in the breakage of the flax roving at the dislocations,affecting flax roving’s quality.(2)Based on the quantitative analysis of infrared spectroscopy,a rapid detection method for the main chemical components of flax fiber was established,and the main chemical components of dislocations could be accurately determined.According to the true values of pectin,hemicellulose and cellulose contents in flax roving and the absorbance data of Fourier transform infrared spectroscopy,the partial least squares regression models for detecting the main chemical components of flax fiber were established and optimized.The pectin content of flax fiber dislocations was 6.97%,and the hemicellulose content was 24.25%,both of which were higher than the corresponding content in the flax roving,while the cellulose content was 41.56%,which was significantly lower than the corresponding content in the flax roving.content.This result showed that there were relatively more gum and less cellulose at the dislocations of flax fibers.If the gum is removed too much,the dislocations are easily broken.(3)The enzymatic degumming process of flax roving was optimized based on the comparative analysis of dislocation structure and composition.According to the research on the optimum conditions for degumming of flax roving by various enzymes,the temperature of enzyme degumming was determined to be 50 ℃ and p H to be 5.0.Combined with the chemical composition content of flax fiber dislocations and the effect of enzyme treatment on dislocations,pectinase,mannanase and xylanase were determined as degumming enzymes,and orthogonal design was used to optimize the compound scheme of degumming enzymes.Finally,the enzyme concentrations of flax roving degumming were determined as follows: pectinase 0.5 mg/m L,xylanase 0.125 mg/m L,and mannanase 0.5 mg/m L.The degumming rate of flax roving in this scheme was 46.81%,which met the requirements of the degumming rate of the finished flax fiber produced by the factory.In addition,the enzymatic degumming removed pectin in a targeted manner and retained more hemicellulose components,reduced the damage of flax fiber dislocation,and obtained higher quality flax fiber.In conclusion,this study carried out visual analysis and composition analysis of dislocations in flax roving.On this basis,the enzymatic degumming process of flax roving was optimized.It can be used to screen the corresponding enzyme-producing strains and promote the improvement and large-scale application of microbial degumming method of flax roving.At the same time,it provides a rapid detection method for the compositions of flax in the degumming process,which has important application value for implementing the precise control of the degumming degree of flax roving,so as to obtain high-quality flax fiber from biological degumming.