八钼酸蜜胺的制备、表征及阻燃协同、抑烟性能

Preparation,Identification,Flame Retardancy and Smoke Suppression of Melamine Octamolybdate

报道了以蜜胺(MA)和七钼酸铵(AHM)制备八钼酸蜜胺的方法,即在搅拌下将1kgMA分批加入盛有1L水的反应器中,再加入1 5kg浓盐酸,加热使MA全部溶解。另外将2 2kgAHM溶于热水中,将所得水溶液再加入MA的盐酸溶液中,生成八钼酸蜜胺(MOM)白色粉末,得率大于95%。用傅里叶变换红外光谱(FTIR)、热失重分析(TGA)、光电子能谱(XPS)及元素分析对标题化合物进行了表征。极限氧指数和UL94V阻燃性能测试表明,聚酰胺6(PA6)中加入质量分数25%的聚磷酸蜜胺(MPP),阻燃PA6的氧指数为29 6,通过UL94V-1阻燃级。如PA6中再加入质量分数2 0%的MOM,由于MOM的阻燃协同效应,阻燃PA6的氧指数可达35 3,通过UL94V-0阻燃级。实验还证明,在聚丙烯(PP)中加入质量分数1%的MOM,PP的阴燃最大烟密度降低50%以上。

Melamine octamolybdate(MOM) was prepared using melamine(MA) and ammonium heptamolybdate(AHM) as starting materials.The preparation procedure is as follows.Add 1 kg MA and 1.5 kg conc. hydrochloric acid to 1 L water and heat the mixture to obtain a clear solution A.At the same time,dissolve 2.2 kg AHM in hot water to obtain solution B.Addition of solution B into solution A gives MOM as white powder in >95% yield.Molecular structure of MOM was identified by FTIR,TGA,XPS techniques and elementary analysis.The flame retardant synergism of MOM with melamine polyphosphate(MPP) in polyamide 6(PA6) and the smoke suppression of MOM in polypropylene(PP) were measured.Experimental results show that the limiting oxygen index(LOI) of PA6 flame-retarded by 25%(mass fraction,based on PA6) of MPP is only 29.6,and its UL94 flame retardancy reaches V-1 grade.But addition of 2.0%(mass fraction) of MOM to MPP can considerably improve the efficiency of MPP,resulting in the LOI and UL94V grade of 35.3 and V-0 grade respectively for the flame-retarded PA6.In addition,1%(mass fraction) of MOM can decrease the maximum smoke density(afterglow) of PP by a factor of 50%.