Preparation And Performance Study Of Flame Retardant/antibacterial Lyocell Fabri

Lyocell fiber,as a new regenerated cellulose fiber,has the advantages of comfort,breathability,excellent mechanical properties and degradability.It is widely used in the production and living of human beings.However,the limiting oxygen index(LOI)value of lyocell fiber is only about 18%.It is easy to ignite and catch fire,which threatens the safety of human life and property and limits its application in high fire risk sites.In addition,the good hygroscopicity and breathability of lyocell fiber results in suitable breeding conditions for microorganisms.The breeding of bacteria will not only destroy the physical properties of fiber,but also increase the risk of disease transmission.Therefore,the development of flame retardant and antibacterial lyocell fabric has become an important research topic related to human life.In the first part,ammonium salt of diethylene triamine penta methylene phosphonic acid(ADTPMPA),an effective phosphorus-nitrogen flame retardant,was synthesized by the reaction of DTPMPA and urea,and then it was covalently bonded with lyocell fabric by pad-dry-cure finishing process.At the same time,the phosphonic acid group in the flame retardant was used to adsorb silver ions,so that the reduced nano silver was firmly combined on the surface of the fabric,the fabric could achieve flame retardant and antibacterial effect.The results showed that the char residue of flame retardant and antibacterial lyocell fabric in nitrogen and air atmosphere were 42.84 wt% and 19.00 wt% at 800℃,respectively,indicating the char-forming ability was significantly improved.Compared with the pure lyocell fabric,the LOI value of the flame retardant and antibacterial lyocell fabric was increased from 18.6% to 42.1%,and the peak heat release rate(PHRR)and total heat release(THR)values were reduced by 95.6% and 89.1%,respectively.The antibacterial test showed that the antibacterial zone width of modified lyocell fabric against Escherichia coli(E.coli)was 5.8 mm,and the antibacterial zone width of modified lyocell fabric against Staphylococcus aureus(S.aureus)was 4.3 mm.These results indicated that the modified fabric had excellent flame retardant and antibacterial properties.In the second part,based on tris(2-hydroxyethyl)isocyanurate(THEIC),a phosphorus-nitrogen intumescent flame retardant was designed and synthesized,and then it was covalently bonded with lyocell fabric by pad-dry-cure finishing process.At the same time,the phosphoric group in the flame retardant was used to adsorb copper ions on the surface of the fabric,and then they were reduced to nanoparticles,so that the fabric can achieve flame retardant and antibacterial effect.The results showed that the char residue of flame retardant and antibacterial lyocell fabric in nitrogen and air atmosphere were 48.56 wt% and 27.30 wt% at 800℃,respectively,and the char-forming ability was significantly improved.Compared with the pure lyocell fabric,the LOI value of the flame retardant and antibacterial lyocell fabric was increased from 18.6% to 35.8%,and the PHRR and THR values were decreased by87.3% and 34.5%,respectively.The antibacterial test showed that the antibacterial circle widths of modified lyocell fabric against E.coli and S.aureus were 5.3 mm and4.6 mm,respectively.These results showed that the modified fabric had excellent flame retardant and antibacterial properties.