| Cotton fabrics are widely applied in human’s life due to excellent mechanical properties, great hygroscopicity and wearing comfort-ability. However, cotton fiber is easily flammable, because the β-D glucose in the molecules will melt under the heat. Considering the cotton fiber is easy to burn, which could causes the fire. The potential ignitability of cotton fiber seriously threatens people’s life and property safety. Therefore, improving the flame retardant of cotton fabric will be our priority. The halogen free flame retardant cotton fabric treated by the formaldehyde-free durability has been becoming a hot spot of resent studies owing to the strict environmental protection policies. The radial sensitivity phosphorus monomer is grafted onto the cotton fiber via electron beam irradiation, which is the effective way to obtain halogen free flame retardant of formaldehyde-free durability.In this paper, the acryloxy nitrogen phosphrous flame retardant monomer P-N with the radial sensitivity was synthesized firstly, and the structure was characterized by Fourier Transform Infrared, Nuclear Magnetic Resonance and Element Analysis. Then the cotton fabric was put in the flame retardant monomer by soaking and rolling two times, and the flame retardant cotton fabric was obtained via Electron Beam Irradiation under the nitrogen protection. The influence factors of grafting rate such as monomer concentration, sorts and concentration of crosslinking agent, padding process and rolling allowance, irradiation dose were investigated lastly. The structure, flame retardant performance, mechanical performance of cotton fabric were researched by FTIR, LOI, vertical combustion, TGA, SEM and strength test.The image analysis of FTIR and SEM showed that the flame retardant monomer have been grafted onto the surface of cotton fiber. The graft rate was influenced by lots of factors, and the monomer concentration is the primary one. The following was the regularity of the flame retardant monomer grafting cotton fabric: the grafting rate increases with the increase of monomer concentration, which changed lowly when the concentration had reached 60%. As the increasing of crosslinking agent concentration, the grafting rate increased firstly then decreased, which achieved the maximum value when concentration of crosslinking agent is 4%. As the increase of irradiation dose, the grafting rate first increased firstly then decreased, which is not obvious to increase when irradiation dose reach 90 KGy and maintain constantly when irradiation dose reached higher than 120 kGy. When the liquid rate was controlled at about 100%, the utilization rate of the flame retardant was the largest at 71%. The results of the whiteness testing and mechanical properties showed that the cotton fabric’s whiteness and strength were decreased slightly after the modification of flame retardant grafting, and the stiffness and frictional resistance were better contrarily. With the increase of grafting rate, the LOI of flame retardant modified cotton fabric was increased, and the vertical burning char length was lower. As the increase of the washing times, the LOI of flame retardant modified cotton fabric was decreased slowly, which showed that flame retardant fabric had excellent washing resistance. The results of TGA and carbon residue of SEM showed that nitrogen phosphorus flame retardant played the important role of the condensation phase in the cotton flame retardant modification. |
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