Study On Flame Retardant Modification Of Polyacrylonitrile Fiber Fabric Surface

Polyacrylonitrile fiber occupies an important position in the textile industry with its soft,fluffy,bright color and other excellent properties.But the LOI value of the polyaciylonitrile fiber is only about 17%and it is extremely flammable.Furthermore,toxic gase was released in the combustion process.Therefore,the development of flame retardant polyacriylonitrile fiber can not only expand its application scope,but also has important practical significance.(1)Aiming for increasing the flame retardancy of polyacrylonitrile fiber fabric,an organic-inorganic hybrid silane coating doped with polyphosphorus acid(PPA)was prepared using tetraethoxysilane(TEOS)as the precursor by sol-gel technique.The analytical techniques including Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and scanning electron microscope(SEM)confirm the successful silicon and phosphorus-doped silicon coating on PAN fabric.Obviously,the char residue values at 800? the phosphorus-doped silica coated PAN fabric samples were observed to increase 25.92%,than that of the control PAN fabric sample.The peak and total heat releases of the phosphorus-doped silica coated PAN fabric significantly reduced by 55%and 58%of that of PAN fabric,respectively.Besides,both peak values of smoke production rate(pSPR)and total smoke production(TSP)are remarkably reduced.The results show that the coated layer can effectively improve the thermal stability,and strengthen the ability to form a thermally stable and condensed barrier for heat and mass transfer.Furthermore,the phosphorus-doped silica-coated PAN fabric provided a novel and efficient method to prepare flame retardant PAN fabric with attractive features.(2)An intumescent flame retardant coating composed of SiN(+)and phytic acid(—)was prepared based on layer by layer assembly and sol-gel technique applied to Surface retardant modification of polyacrylonitrile fiber fabric.The analytical techniques including Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and scanning electron microscope(SEM)confirm that SiN(+)and phytic acid(-)LbL coating successfully finishing on polyaciylonitrile fiber surface.The thermal analysis and cone calorimetry analysis showed that the thermal stability of the treated polyacrylonitrile fabric was greatly improved and the amount of char residue values were increased significantly.The peak and total heat releases of the LbL coated PAN fabric significantly reduced by 66%and 73%of that of PAN fabric,respectively.Besides,both peak values of smoke production rate(pSPR)and total smoke production(TSP)are remarkably reduced.The limit oxygen index of the LbL coated PAN fabric was up to 33.2%.Therefore the flame retardancy of the treated polyaciylonitrile fiber fabric was significantly improved.