Construction Of Phosphorus-Nitrogen-Silica Flame Retardant System And Application In Flame Retardant Cotton Fabrics

Cotton fabrics with low LOI are easily ignited in air,so their application is limited.In this work,a method for construction of phosphorus,nitrogen and silicon flame-retardant systems via layer-by-layer?LbL?assembly and their application in cotton fabrics were provided.During combustion,phosphorus-nitrogen containing flame retardants did not produce toxic gases and fumes,and their synergistic effect had been confirmed.The introduction of the silicon-containing flame retardant further improves the flame retardant property of the phosphorus-nitrogen-containing flame retardant.In this work,poly[3-?5,5-cyanuricacidpropyl?-siloxane-co-trimethyl ammoniumpropyl siloxane chloride]?PCQS?was synthesized and coated onto cotton fabrics with phytic acid?PA?via layer-by-layer?LbL?assembly to prepare flame retardant and antibacterial cotton fabric.The nanosilica covered with polyethyleneimine?SiO₂-PEI?sol was prepared,and SiO₂-PEI and PA were coated onto cotton fabric to prepare cotton fabrics with excellent flame retardant effect.The SiO₂-PEI sol,polyphosphoric acid?PPA?and hydrophobic agents?REPELLAN FF?were coated onto cotton fabrics to prepare flame retardant and hydrophobic cotton fabrics.Firstly,PCQS was synthesized from cyanuric acid,chloropropyltriethoxysilane and trimethylamine,and characterized by infrared spectroscopy?FT-IR?.PCQS and PA were coated onto cotton fabrics by layer-by-layer?LbL?assembly.The morphology and structure of the treated cotton fabrics were characterized by scanning electron microscopy?SEM?,infrared spectroscopy?FT-IR?and elemental analysis?EDX?.As the layer numbers increased,the weight gain rate of the treated cotton fabrics increased continuously,and the weight gain rate of cotton fabrics reached 20.4%when self-assembled layers was 30.The thermal property,flame retardancy,antibacterial and mechanical properties of the treated cotton fabrics were investigated.After chlorination,the treated cotton fabric with 30 layers had good thermal property?carbon residue was 34%?and flame retardancy?LOI value of 28.5%?,and excellent antibacterial property?100%bacterial reduction of S.aureus and E.coli O157:H7 within 1 min of contact time?.Secondly,a novel hybrid organic-inorganic intumescent flame-retardant composed of polyethyleneimine?PEI?wrapped nanosilica?SiO₂?and phytic acid?PA?,was coated on cotton fabrics by layer-by-layer?LbL?assembly.The morphology and structure of the treated cotton fabrics were characterized SEM,FT-IR and EDX.The weight gain rate of the treated cotton fabrics increased continuously with the increase of layer numbers.The thermal property,flame retardancy and mechanical property of the treated cotton fabrics were investigated.SiO₂-PEI/PA coated cotton fabrics had good thermal property?carbon residue was 41%?and excellent flame retardancy?LOI value of 33.7%?when the number of layer numbers reached 7.Thirdly,a flame-retardant coating composed of SiO₂-PEI and polyphosphoric acid?PPA?was first deposited on the cotton fabric,and then the REPELLAN FF was finished on the cotton fabric by pad-dry-cure process to prepare flame retardant and hydrophobic cotton fabrics.The treated cotton fabrics were characterized by SEM,FI-IR and EDX.The thermal property,flame retardancy,hydrophobicity and mechanical property of the coated cotton fabrics were investigated.Cotton fabrics coated with SiO₂-PEI/PPA/REPELLAN FF had good flame retardancy and hydrophobicity with LOI value of 28.2%and the contact angle of 142°±1°.