Study On Properties And Identification Of Different Crosslinking Types Of Lyocell Fibers

According to the degree of cross-linking,Lyocell fiber can be divided into uncross-linked type（G100）,semi-cross-linked type（LF）and fully cross-linked type（A100）.Different crosslinking Lyocell fabric produces fibrillation phenomenon is different,have different performance,clothing market to do not produce the phenomenon of fibrillation crosslinking type fiber demand has been high,crosslinking and crosslinking model fiber price difference is very big,about different crosslinking type in the identification of Lyocell,there is no accurate determination method.Therefore,it is very urgent to find a method to identify different cross-linked Lyocell fibers,which is of great significance to the production and inspection of fiber fabrics and the regulation of domestic and foreign market trade.In this paper,based on the different properties of different crosslinking types of Lyocell fibers,through the study of fiber structure,basic properties,swelling and dissolution properties,to explore a method to accurately identify different crosslinking types of Lyocell fibers,and to study the factors affecting the crosslinking properties of crosslinking types of fibers.First of all,The molecular structure and basic properties of three kinds of Lyocell fibers were studied by using modern analysis and testing techniques.The crystallinity of G100,LF and A100 was calculated to be 62.17%,59.64%and 66.23%,respectively by X-ray diffractometer.The IR and Raman spectra of the three Lyocell fibers showed that the group structures of the fibers were not different.In the thermal performance analysis,taking the thermal decomposition mass loss as the index,the research shows that the thermal decomposition mass loss rate of uncross-linked G100 is 80%,and the mass loss rate of semi-cross-linked LF and fully cross-linked A100 is 70%.The study of electrical and hygroscopic properties showed that the mass specific resistance(Ω·g·cm^-2)of G100,LF and A100 were0.88×10⁸,1.28×10⁸ and 3.16×10⁸,respectively,and the standard moisture return rates were13.47%,13.52%and 12.59%,respectively.Secondly,The swelling and dissolution properties of different crosslinked Lyocell fibers were studied.The wet expansion rate and water retention value of fiber were tested in different alkali solutions,and the results showed that the size of the wet expansion rate and water retention value of fiber were:A100>LF>G100.The solubility of fiber in hydrochloric acid,sulfuric acid,formic acid/zinc chloride and zinc chloride was studied.The results showed that when the temperature was 25℃,the dissolution time of G100,LF and A100 in 37%hydrochloric acid was 6 min,20 min and 25 min,respectively.In 65%dilute sulfuric acid,the dissolution time is 27 min,34 min,60 min,and in 70%dilute sulfuric acid,the dissolution time is 1min,10 min,16 min,respectively.When anhydrous zinc chloride:98%formic acid:water=20:68:12,the dissolution time was 24 min,30 min,45 min,respectively.The dissolution time in 70%Zn Cl₂ solution at 90℃was 30 min,180 min and 450 min,respectively.Lyocell fibers of different crosslinking types have little difference in dissolution time in hydrochloric acid,sulfuric acid,formic acid/zinc chloride solvents,which cannot be used as a basis for fiber identification.However,at 90℃,the dissolution time in 70%Zn Cl₂ aqueous solution is very different,which can accurately distinguish the three kinds of Lyocell fibers.Finally,The fibrinization properties of three kinds of Lessel fibers were studied.The results showed that G100 was the most prone to fibrinization,LF had less fibrinization,and A100 had no fibrinization.For textile enterprises reflect the type of crosslinking lyocell fabric in the process of taking easy pilling phenomenon,discovered the type printing and dyeing processing destroys the crosslinking lyocell crosslinking performance,further study found that the alkali treatment affect cross-linking type fiber cross-linking bond,Na OH treatment by design type crosslinked lyocell orthogonal test,The effect of Na OH treatment on crosslinking performance of crosslinked Lyssel fiber was analyzed.The results show that sodium hydroxide treatment has a great influence on the cross-linking performance of cross-linked Lyssel fiber,and the influencing factors are as follows:Sodium hydroxide concentration>treatment temperature>treatment time,after Na OH solution treatment,cross-linked A100 fiber is easy to produce fibrinization phenomenon.After Na OH treatment,the mass loss rate of Lyser G100,LF,A100at the termination of thermal decomposition is:85%,82%,82%,respectively,and the crystallinity is:60.63%,58.32%,64.89%.