采用层层自组方法在剑麻纤维素微晶(SFCM)表面吸附天然聚电解质壳聚糖(cH)和植酸(PA),构筑可再生CH/PA阻燃涂层,用Zeta电位、热重分析(TGA)、场发射扫描电镜(FESEM)、垂直燃烧测试(VFT)和燃烧量热仪(MCC)等手段对复合材料进行了表征。Zeta电位和FESEM结果显示,在CH和PA吸附过程中电位正负交替变化,SFCM表面局部位置被一层凸起的涂层包覆。TGA和FESEM结果表明,随着CH/PA层数的增加复合材料的初始分解温度由299℃降低至257℃,残炭率由5.41%提高至37.64%,SFCM(CH/PA),的TG残炭物表面未出现螺旋状收缩,纤维素形貌基本上不变;VFT结果显示,SFCM(cH/PA),续燃时间(39S)比纯SFCM(150s)缩短了111S。MCC结果表明,SFCM(CH/PA),的热释放速率峰值(pkHRR)~热释放总量(TotalHR)与纯SFCM相比分别减少70.6%~FI79.2%,表明CH/PA涂层具有明显提高SFCM阻燃性能的作用。
Sisal fiber cellulose microcrystallines (SFCM) was coated with a fully renewable flame-re- tardant coatings consisted of cationic chitosan (CH) and anionic phytic acid (PA) via layer-by-layer (LbL) assembly. The structure and properties of the formed microcrystallite composite were characterized by Zeta potential, TGA, FESEM, VFT, and MCC methods. Zeta potential and FESEM results show that the surface charge of the coated cellulose microcrystallites reversed due to the adsorption of polyelectrolyte during multilayer deposition process. TG analysis show that the initial decomposition temperature of the composites decreased from 299~C to 257~C and the residues increased from 5.41% up to 37.34% with the increase of CH/PA film layers. Examination Of SFCM(CH/PA)s residues by FESEM revealed that the distinct fiber structure have been preserved and insignificant fiber shrinkage was observed.Vertical com- bustion testing (VFT)results show that for SFCM(CH/PA)5. in comparison with the plain SFCM, the after- flame time is drops from 150 s down to 39 s; the pkHRR and total heat release (HR)exhibit great reduc- tion of 70.6% and 79.2% respectively. These results demonstrate that the CH/PA coating has obviously improved the flame retardant performance of SFCM.