Synthesis Of Aminothiourea-based Antibacterial Agents And Application In Functional Lyocell Fibers

Lyocell is a new raw material for textile and apparel fabrics introduced in the 20 th century.Compared to traditional viscose fibers,Lyocell fibers not only have the comfort,feel and dyeing properties of cotton,but are also made from renewable resources and have environmental advantages.Its advanced process makes it possible to manufacture the fiber with a solvent recovery rate of 99.7%,without the release of toxic substances,and it is biodegradable,which is beneficial to the environment and human health.Therefore,it is energy-saving,environmentally friendly and sustainable.However,the poor flame retardancy and antimicrobial properties of Lyocell fibers greatly limit their applications.Therefore,studying how to give it dual functions of flame retardant and antibacterial not only helps to expand its application fields but also is in line with the sustainable green development strategy.In this study,an antibacterial agent and a flame retardant were introduced to Lyocell fiber by covalent coupling,and Lyocell fiber with dual functions of flame retardant and antibacterial was designed and prepared.The ultimate oxygen index values were tested by an intelligent critical oxygen index analyzer,and the structure and other properties were characterized using analytical instruments.Structural analysis of the synthesized antimicrobial agents was carried out using instruments such as mass spectrometry and nuclear magnetic hydrogen spectrometry.The synthesized antimicrobial agent was also introduced to the flame retardant modified fibers by covalent coupling,and the Lyocell fibers modified with flame retardant antimicrobial agent were characterized and tested for their antimicrobial properties using instruments such as thermal weight loss analyzer and Fourier transform infrared spectrometer.The results of the study showed that the surface of the fiber treated with antimicrobial agent and flame retardant was rougher than the original sample,and the surface showed grooves and cracks as well as original fibrillation.Although the mechanical properties of the modified fibers decreased,the fibers treated with the coupling agent butane tetracarboxylic acid(BTCA)and the flame retardant [3-[(hydroxymethyl)amino]-3-carbonyl propyl]-phosphonic acid dimethyl ester(FRC-2)showed the least decrease in breaking strength and the mechanical properties met the standards for subsequent processing.The thermal stability of the modified fibers was improved,and the flame retardant properties were enhanced,and their ultimate oxygen index was increased.The flame retardant was FRC-2 modified with the best effect,and the LOI value reached 25.7%.The modified fiber has good antibacterial effect on Staphylococcus aureus and poor antibacterial effect on Escherichia coli,among which the antibacterial agent GT1 has the best antibacterial performance.Therefore,when the coupling agent is BTCA,the flame retardant is FRC-2 and the antimicrobial agent is GT1,the modified Lyocell fiber has the best flame retardant and antimicrobial performance.The bifunctional flame retardant and antibacterial Lyocell fiber successfully prepared in this project provides a new idea and direction for the application expansion of Lyocell fiber.