Determination Of Chemical Components In Flax Fibers

The basic component of flax fiber is cellulose,and it also includes non-cellulose components such as fat wax,pectin,hemicellulose,and lignin.These components have a negative impact on further improving the fineness,elasticity,uniformity and adsorption of the fiber..In the process of fiber processing,due to the difference in the content of each component,it will often affect the finishing of fiber processing and dyeing.For example,in the actual production process,grease and wax will easily cause the fiber to wind on the roller and affect the quality of the yarn;It is easy to make the fiber entangled on the drum and affect the dyeing performance of the fiber;lignin affects the roughness and hardness of the fabric,and to a certain extent also causes fabric defects.Therefore,before spinning,it is very necessary and important to clarify the content of various components and take corresponding measures to improve its spinnability.Therefore,the test and analysis of the composition content of flax fiber have an important impact on the spinning process and the quality of the final product.At present,there is no method standard for the detection of flax components at home and abroad.This paper studies and formulates quantitative analysis methods for the chemical components of cellulose,hemicellulose,lignin,pectin,and lipid wax in flax fiber.Method for testing and other key core technologies,established an efficient,stable,and simple chemical composition quantitative method,fills the current gaps in international and domestic related fields,and provides an effective evaluation method for the quality control of hemp fiber in each link of spinning.This test The establishment of the method will have an important influence on the actual production and international trade of flax and other hemp fibers.The main research contents are as follows:(1)Lipid waxy: Three extraction solvents were initially screened through experiments:phenethyl alcohol mixed solution(volume ratio 2:1),toluene-ethanol mixed solution(volume ratio2:1),acetone,and the amount of solvent,drying temperature,and extraction Factors such as solution and fiber were studied and confirmed by GC-MS analysis.The study found that using a mixture of phenethyl alcohol(volume ratio 2:1)as an organic solvent,Soxhlet extracts the fat and wax components of the fiber,and then the fiber is dried to calculate the fiber weight loss to obtain the fat and wax content;this method is due to benzene The self-coupling is adsorbed on the fiber,which leads to the phenomenon of less weight loss of the fiber,and finally causes the deviation of the lipid wax test value.At the same time,it is also found that the low boiling point components in the fat wax will volatilize at high temperature,resulting in a small test value.Through continuous optimization,the best extraction reagent and test method are determined as follows: acetone is used as the organic solvent for extracting fat wax,after Soxhlet extraction for 4 hours,the number of refluxing is 4-6/h,the fiber is dried at 105 ℃ for 4 hours,and finally Calculate the fiber weight loss to get the fat wax content.Solved the problem of strong carcinogen benzene as the extraction solvent,and developed and broke through the key core technology of using ecological green methods for detection.(2)Water-soluble matter: The influence of different extraction time and temperature on the water-soluble matter test of flax fiber was studied,and colorimetric method and HPLC analysis method were adopted.The study found that during the water-soluble matter test,hemicellulose will be affected by boiling at high temperature.A certain degree of hydrolysis,but the percentage of hydrolyzed content in the total fiber mass is not more than 0.2%,which can be ignored;the best method is finally determined: at 100℃,use 150 m L deionized water for the flax fiber after the fat wax is extracted Boil for 4 hours,and obtain the water-soluble content by analyzing the quality of the fiber before and after treatment.(3)Pectin: Analyzed and studied the influence of three different test methods: mass method,carbazole colorimetric method,sodium thiosulfate titration method and extraction time on the test of pectin content in flax fiber;the study found that water-soluble pectin would be Hydrolysis under high-temperature boiling conditions,using the water-soluble substance test sample to test the pectin content,will result in the total pectin content in the flax sample being too small;through research and analysis,the final test method is determined as follows: The flax sample after the extraction was boiled with 5g/L ammonium citrate solution for 4h,and the total pectin content was determined by sodium thiosulfate titration.(4)Hemicellulose: Analyzed and studied the influence of two different test methods: mass method and DNS reagent colorimetric method on the test of hemicellulose content in flax fiber;the research found that compared with the method of analyzing hemicellulose content by mass method,DNS colorimetric method has the characteristics of high sensitivity and small error;through research and analysis,the final test method is determined as follows: use 2 mol/L hydrochloric acid solution to boil a sample of flax after extracting pectin for 1 hour to make half Cellulose is hydrolyzed,and the concentration of total reducing sugars is determined by DNS colorimetry,and finally the content of hemicellulose is obtained.(5)Cellulose: Analyzed and studied the effects of two different test methods,hypoiodic acid oxidation method and anthrone colorimetric method,on the test of cellulose content in flax;the study found that both methods can effectively determine the cellulose content,but hypoiodic acid the oxidation method has the characteristics of high precision,convenient operation,and low requirements for experimental equipment.The final study determined the test method as follows:use the flax sample after hemicellulose extraction,treated with 75% concentrated sulfuric acid,and finally use hypoiodic acid oxidation method Calculate the cellulose content in flax fiber.Through analysis and research,the right test method can be formulated to better test the content of each component of flax fiber.The draft ISO standard for the analysis and testing of various components in flax fiber is formulated,and it provides reference for other fiber component testing.