Study On Flame Retardant Modification And Properties Of Polyacrylonitrile Fiber Fabric By UV Grafting

In recent years, fire accidents are reported frequently in the world, which bring serious threat to people’s life and property security. Textiles has become a major hidden danger of indoor fire, countries have to formulate a series of combustion test methods and evaluation standards and regulations, strictly regulate the textile standard of flame retardant in public places. Polyacrylonitrile fiber is a synthetic fiber which is made of polyacrylonitrile or acrylonitrile content more than 85% of acrylonitrile copolymer. It has the advantages of soft, fluffy, light fastness, easy dyeing, and properties similar to wool, so it’s called synthetic wool. PAN fiber is widely used in clothing, decoration, industry and other fields. The biggest disadvantage of conventional PAN fiber is flammable, and its limiting oxygen index is only 17-18.5. It is one of the most easy combustion synthetic fibers. In order to accelerate the development of varieties of flame retardant PAN fiber, we should find a more effective way to reduce cost and improve the performance of price ratio to achieve mass production and localization, and enhance its market competitiveness.In the first part of the study, the acrylic acid (AA) monomer was grafted onto the surface of polyacrylonitrile (PAN) fiber fabric by ultraviolet grafting technology and PAN-g-AA fabric was obtained. The thermal properties of the PAN fabric were improved, and the COOH was introduced into the PAN. Prepare for subsequent chemical modification. The effects of illumination time, illumination distance, monomer concentration, initiator concentration and reaction temperature on the graft yield were discussed. Under different grafting rate of PAN fabric were analyzed by infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), thermal gravimetric (TG), scanning electron microscopy (SEM).In the second part of the study, the PAN-g-AA fabric is chemically modified by thionyl chloride, ethylenediamine, phosphoric acid and other chemical reagents. Successfully introduced nitrogen and phosphorus, and got the flame retardant polyacrylonitrile fabric. The synergistic effect of nitrogen and phosphorus in the flame retardant of the PAN can improve the flame retardant properties of the fiber. The infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS) analysis showed that in different stages of the flame retardant modification were conducted successfully. X-ray diffraction (XRD) analysis showed that after each stage of flame retardant modification the degree of crystallinity of PAN fabric decreased. Through limiting oxygen index (LOI), differential scanning calorimetry (DSC), thermal gravimetric (TG) and scanning electron microscope (SEM) analysis shows that the thermal performance of the flame retardant PAN fabric is improved. The flame retardant PAN fabric has good flame retardant performance and belongs to the flame retardant mechanism of condensed phase and gas phase.In this paper, a new method for preparing the flame retardant polyacrylonitrile fabric is obtained by the combination of UV and chemical modification.