Synthesis Of Novel Reactive Flame Retardants With Phosphonic Acid Ammonium As Reactive Groups For Cotton Fabric And Study On Flame Retardant Property

Cotton fabrics are widely used in clothing,home furnishing products and various industrial textiles due to its excellent properties such as good hygroscopicity,certain wear resistance,static resistance,good permeability.However the limiting oxygen index of cotton fabric is about 18%,belonging to flammable materials.According to statistics,50% of fires in the world were caused and spread by textiles.Therefore,in order to reduce the fire risk of cotton textile,build a fire barrier,improve security of people's life and property,the research about flame retardant finishing of cotton fabric is the hotspot at home and abroad.At present,flame retardant finishing agent Pyrovatex CP and Proban are widely used,although the flame retardant effect and durability are very excellent,the finished cotton fabrics will release formaldehyde,which is harmful to human health.So the development of novel,high efficiency,reactive and durable flame retardants for cotton fabric is very important.The main research in this context contents:In this paper,flame retardant agent diethylenetriaminepenta methylene phosphonic acid ammonium(ADTMPA)was synthesized by using diethylenetriaminepenta methylene-phosphonic acid(DTPMPA)and urea as raw materials.And ammonium salt of ethylenediamine tetramethylenephosphonic acid(AEDTMPA)was synthesized by using ethylenediamine,phosphorous acid,methanal and urea as raw materials.The structure of ADTPMPA and AEDTMPA was characterized by nuclear magnetic resonance 1H NMR,13 C NMR,31 P NMR.When the concentration of ADTPMPA was 70g/L,the weight gain rate of finished cotton fabric was 14.42%,the LOI value reached 40.0%,the finished cotton fabrics exhibit good flame retardant property.After 30 times washing,the LOI value was 28.0%,ADTPMPA belonged to the semi-durable flame retardant.The vertical burning test,cone calorimeter andthermogravimetric tests results showed that the treated cotton fabrics had lower decomposition temperature,higher carbon residual than that of original cotton fibers,and the thermal stability of finished cotton fabric was improved,the treated cotton fabrics showed excellent flame retardant property.Treated cotton fabric showed condensed phase flame retardant mechanism.Fourier transform infrared spectroscopy indicated that there were P-O-C bonds on the finished cellulose,that was the reason why the finished fabrics had very good durability.Scanning electron microscopy showed that the finished cotton fibers became swollen,and smoother than that of original cotton fibers.And X-ray diffraction revealed there was some formation of cellulose II in the finishing process.The physical properties of cotton fabrics such as tensile strength,crease elasticity,stiffness and whiteness were characterized,the results showed that the strength of the cotton fabric after finishing decreased a little and the anti-wrinkle performance was improved,which ensure the treated fabrics could be applied in market.For AEDTMPA,when the concentration of AEDTMPA was 60g/L,the LOI value of finished cotton fabric was 40.5%,after washed 30 times,the LOI value was 26.4%.Then the finished cotton fabrics could be used as a semi permanent flame retardant textiles.When the concentration is 80g/L,the LOI value of finished cotton fabric reached to 43.6%,after 50 times washing,the LOI value was 28.3%.Therefore the finished cotton fabric could be used as a permanent durable flame retardant textiles.The results of vertical burning test,cone calorimeter and thermogravimetric showed that the treated cotton fabrics had excellent flame retardant property,the PHRR and THR were very low,leaving more residues after burning than that of untreated cotton fabrics.AEDTMPA treated cotton fabric had better flame retardant property,higher LOI values and residues than that of ADTPMPA treated cotton fabrics.The morphologies of the cotton and residues of the fabrics were investigated by scanning electron microscopy,the results showed that the finished cotton fibers were swollen,and the the structure of burned fabric was integrated,a few bubbles could be seen on the burned fibers surface,which showed that AEDTMPA had condensed phase and intumescent flame retardant mechanism.Fourier transform infrared spectroscopy showed that the flame retardant molecules were combined on cellulose with covalent bonds.So the durability of finished cotton fabrics was excellent.And X-ray diffraction revealed the crystal structure of treated cotton was almost not affected.The physical properties of finished cotton fabric such as whiteness,strength and stiffness were kept well.The wrinkle elastic recover angles of AEDTMPA treated cotton fabric could reach to 260.0o,AEDTMPA could be used as anti-wrinkle finishing agent.The novel reactive flame retardant with phosphonic acid ammonium as reactive groups for cotton fabric does not contain formaldehyde and halogen,and the finished cotton fabrics showed excellent flame retardant property and durability.Then they have good application prospects.