聚乙烯亚胺/植酸自组装整理棉织物的阻燃性能表征

Flame retardant characterization of cotton fabrics self-assembled by polyethyleneimine/phytic acid

为解决植酸(PA)的强酸性对阻燃棉织物(COT)的影响及棉织物阴燃问题,以聚乙烯亚胺(PEI)和PA为原料,利用层层自组装(LBL)和喷涂工艺,在棉织物表面制备PEI/PA阻燃涂层,探讨复配阻燃剂的协同阻燃效果。用热重分析、极限氧指数(LOI)仪、垂直燃烧测试仪等对阻燃整理前后的棉织物进行表征。研究表明:植酸、聚乙烯亚胺的初始分解温度下降,先于主体吸热降解,有效抑制织物初始热裂解,促进材料低温炭化。在升温阶段,聚乙烯亚胺热裂解产生N2和NO2等惰性气体,形成隔氧保护层,起延缓织物降解作用;植酸降解产生磷酸或偏磷酸,催化纤维素脱水炭化,有促进低温炭化趋势。聚乙烯亚胺/植酸复配整理织物,损毁长度减少到3cm,续燃时间和阴燃时间可达到0s,LOI值由18.1%提升到38.2%,PEI所带正电荷与PA所带负电荷的磷酸基团通过静电相互作用改善了PA的酸性性质,有效解决棉织物的阴燃及植酸强酸性对棉织物的影响问题,并达到阻燃目标。

In order to solve the influence of strong acidity of phytic acid(PA)on flame retardant cotton fabric(COT)and the problem of smoulder of cotton fabric,PEI/PA flame retardant coating is prepared on the surface of cotton fabric by using layer self-assembly(LBL)and spraying process with polyethyleneimine(PEI)and bio⁃mass material phytic acid(PA)as raw materials,and the synergistic flame-retardant effect of the compound flame retardant is explored.Characterization is performed by thermos-gravimetric analysis,limiting oxygen in⁃dex(LOI)meter,and vertical combustion tester.The study shows that phytate and polyethyleneimine feature the decreased initial decomposition temperature and can degrade before the main body absorbed heat,which effectively inhibite the initial thermal cracking of the fabric and promote the low temperature charring of the ma⁃terial.In the heating stage,the thermal cracking of polyethyleneimine produces inert gases such as N2 and NO2,forming a protective layer of oxygen barrier and slowing down the degradation of fabric;the degradation of phytic acid produces phosphoric acid or metaphosphoric acid,which catalyzes the dehydration and carboniza⁃tion of cellulose and has the tendency to promote low-temperature carbonization.The finished fabric with poly⁃ethyleneimine/phytic acid compound system,features the length of damage reduced to 3 cm,the time of re⁃newed combustion and negative combustion time of 0 s and its LOI value from 18.1%to 38.2%.The positive charge of PEI and the phosphoric acid group of negative charge of PA through electrostatic interaction can im⁃prove the acidic nature of PA,which can effectively solve the problem of negative combustion of cotton fabrics and the strong acidic effect of phytic acid on cotton fabrics,and achieve the goal of flame retardant.