Preparation Of A Novel Multifunctional Phosphorus-nitrogen Base Flame Retardants And Application In Cotton Fabric

Cotton fabric is widely used in the fields of clothing,household textiles and industrial textiles because of its a series of excellent characteristics.However,the cotton fiber which is the raw material of cotton fabric is flammable material,and its group is divided into polysaccharide,which is easy to breed bacteria.There are security risks to the fabric and human body.thus its application in various areas is limited.In this paper,biguanide(TD)was synthesized by addition reaction with dicyandiamide(DCA)and trimethylol aminomethane(THAM).Then,esterification and acid-base neutralization reaction were carried out with phosphorus pentoxide(PA)and urea.Finally a novel multifunctional phospho-nitrogen base flame retardant(APD)with biguanide structure was synthesized.The properties of flame retardant and antibacterial of the substance to cotton fabric were studied.The results of fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance hydrogen spectroscopy(~1H-NMR)showed that APD had been synthesized successfully.Thermogravimetric analysis(TGA)test results showed that the residual carbon content of APD was 15.6%at 700℃,which has the potential to improve the flame retardant property of cotton fabrics.The multifunctional cotton fabric Co-APD was prepared by grafting APD onto cotton fabric.It was confirmed that APD has been successfully grafted onto cotton fabric by Fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and energy dispersive X-ray spectroscopy(EDS).The flame retardant and antibacterial properties of modified cotton fabrics were tested by the ultimate oxygen index(LOI),UL-94 vertical combustion test(VBT),cone calorimeter test(CCT),thermogravimetric analysis(TGA),colony counting method,observation of live/dead bacteria morphology,live/dead bacterial fluorescence staining,antibacterial biofilm test and other characterization methods.The test results showed that Co-APD has excellent flame-retardant and antibacterial properties.When the grafting amount of APD reached 15 wt%,the LOI of Co-APD-15%could reach 34.0%.In nitrogen environment,the residual carbon content of Co-APD-15%could reach 33.31%at 700℃.The maximum heat release rate(PHRR)and total heat release(THR)of Co-APD-15%decreased by 85.4%and 43.7%compared with raw cotton fabric.Meanwhile,the antibacterial rate of Co-APD-15%against Escherichia coli and Staphylococcus aureus reached 96.7%and 99.9%,respectively.Washable performance test showed:After 50 washes,the LOI of Co-APD-5%and Co-APD-10%decreased by 1.0%and 1.2%,respectively,and the LOI of Co-APD-15%was still 27.5%.The antibacterial rate of the three modified cotton fabrics against Escherichia coli decreased by 2.2%,3.8%and 1.6%,respectively.The antibacterial rate against Staphylococcus aureus was reduced by 1.0%,0.8%and 0.7%,respectively.The test results showed that the breaking strength of the modified cotton fabric can retain more than 87.5%of that of the original cotton fabric.