| Mixing dispersion of magnesium hydroxide(MH)with 1-allyl-3-methylimidazolium chloride ionic liquid(IL)and in-situ synthesized dispersion of MH in IL were sprayed on pristine cotton fabric?acid-treated cotton fabric?cellulase-treated cotton fabric?cotton fabric treated with ultraviolet radiation and plasma-treated cotton fabric,respectively.Two immobilization methods,hot air and hot rolling,were applied to immobilize MH onto the surface of fabrics,and then their flame retardant properties were compared.Besides,SEM,ATR,XRD,DSC and TGA were employed to characterize pristine cotton fabric,surface-treated cotton fabrics and cotton fabrics immobilized with MH.The results show that the particle size of MH in in-situ synthesized dispersion of MH/IL was smaller than that of mixing dispersion.Under the condition of MH amount of 5%,spraying temperature of 39 ?,spraying number of 3,circulating immobilization number of 1,hot air temperature of 95 ? with fixed needle plate for tension state and hot air heating time of 6 min,the afterflame time and afterglow time of pristine cotton fabric with MH immobilization ratio of 7.99%,warp shrinkage rate of 1.09%and weft shrinkage rate of 15.24%were 2.4 s and 3.5 s,respectively.Cotton fabric treated with acid for 40 min possessed MH immobilization ratio of 6.99%,warp shrinkage rate of 1.46%,weft shrinkage rate of 21.11%,afterflame time of 3.1 s and afterglow time of 1.3 s.Cotton fabric treated with plasma for 30 min possessed MH immobilization ratio of 7.57%,warp shrinkage rate of 1.63%,weft shrinkage rate of 27.62%,afterflame time of 3.0 s and afterglow time of 3.4 s.Under the process of MH amount of 5%,spraying temperature of 39 ?,spraying number of 3,circulating immobilization number of 1,vacuum drying with fixed needle plate for tension state at room temperature for 2 h,hot-rolling temperature of 90 ? and hot-rolling time of 60 s,pristine cotton fabric with MH immobilization ratio of 7.36%,warp shrinkage rate of 1.40%and weft shrinkage rate of 2.13%possessed afterflame time of 2.0 s and afterglow time of 3.0 s.Cotton fabric treated with acid for 30 min possessed MH immobilization ratio of 6.59%,warp shrinkage rate of 1.81%,weft shrinkage rate of 2.38%,afterflame time of 1.3 s and afterglow time of 2.4 s.Afterflame time of 1.0 s and afterglow time of 2.0 s could be obtained by cotton fabric treated with plasma for 30 min possessing MH immobilization ratio of 8.06%,warp shrinkage rate of 1.56%,weft shrinkage rate of 2.28%.However,there was no obvious improvement in the flame retardant performance of cellulase-treated cotton fabric and ultraviolet radiation treated cotton fabric immobilized with MH in comparing to pristine cotton fabric immobilized with MH.Adsorption peak at 3335 cm-1,2920 cm-1,and 3694cm-1 in ATR spectras of cotton fabrics immobilized with MH were ascribed to-OH and-CH in cellulose molecules and Mg-OH of MH.The appearance of diffraction peaks of 001,100,101,102,110,111 and 103 crystal face due to MH in XRD patterns of cotton fabrics immobilized with MH by two methods suggested that MH particles immobilized onto cotton fabrics has good crystallinity.The diffraction peaks of 101,101,002 and 040 crystal face owing to cotton cellulose I and 101 due to cotton cellulose II in XRD patterns of swelled and washed cotton fabric and cotton fabric immobilized with MH via hot air implied that the swelling of cellulose on the surface of cotton fiber under smaller tension contributed to change the crystal type of cellulose to some extent.Also,MH particles can be observed embedded in the fiber membrane formed after swelling and shrinkage of the surface of cotton fabric with SEM graphs.Compared with pristine cotton fabric,thermal analysis indicated the decrease of weight loss and increase of heat absorption and residual carbon of cotton fabrics immobilized with MH.The result of physical properties analysis and testing show that surface-treated cotton fabrics possessed higher bending rigidity,higher surface friction and coefficient of friction and lower tensile breaking strength than that of pristine cotton fabric.Cotton fabrics immobilized with MH in two methods had a increase in bending rigidity,surface friction and coefficient of friction in comparison to that of pristine cotton fabric.The tensile breaking strength of cotton fabric immobilized with MH via hot air and untreated cotton fabric immobilized with MH via hot-rolling is higher than that of pristine cotton fabric,while treated cotton fabric immobilized with MH via hot-rolling is the opposite. |
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