硼酸锌对膨胀阻燃聚甲醛的协效阻燃研究

为进一步提高膨胀型阻燃剂(IFR)对聚甲醛(POM)的阻燃效果,首先将硼酸锌(ZB)与常用IFR(聚磷酸铵-三聚氰胺-季戊四醇)共混制得ZB-IFR复配膨胀阻燃体系的样品,采用熔融共混法制备ZB-IFR/POM复合阻燃材料;然后利用极限氧指数(LOI)测定仪、垂直燃烧(UL-94)测试法、热重分析(TGA)法、扫描电镜(SEM)、锥形量热仪(CONE)及热重-红外(TG-IR)仪等研究ZBIFR对POM的协效阻燃作用。结果表明:当ZB含量为1%时,所得1.0ZB-IFR/POM的LOI可达55%,UL-94等级为V-0级;其受热膨胀后所得残炭量高,炭层结构致密稳定,且在燃烧过程中的热释放速率(HRR)、质量损失及烟气释放量均最小,火灾性能指数(FPI)相对最高;除此,不含ZB的IFR/POM在受热分解过程中比1.0ZB-IFR/POM放出更多的CO2,说明ZB的加入能有效地抑制复合阻燃材料的充分燃烧,显示出良好的协效阻燃作用。

Synergistic flame-retardant effects of zinc borate in intumescent flame retardant applied on polyoxymethylene

In order to improve flame retardancy of IFR on POM,compound ZB-IFR samples were prepared by blending ZB with commonly used IFR(ammonium polyphosphate-melamine-pentaerythritol),and ZB-IFR/POM flame-retardant composites were made with melt blending method.Then synergistic flame-retardant effects of ZB-IFR on POM were studied by using limiting oxygen index(LOI),vertical combustion(UL-94),thermogravimetric analysis(TGA),scanning electron microscope(SEM),CONE calorimeter and Thermogravimetric-infrared(TG-IR).The results show that when 1%ZB is added,LOI of obtained 1.0 ZB-IFR/POM can reach 55%and UL-94 grade is V-0.And after thermal expansion,the composite has a high char residual content with a compact and stable char layer,and its heat release rate(HRR),mass loss and smoke emission are the smallest during combustion process,so its fire performance index(FPI)is relatively high.Besides,IFR/POM without ZB emits more CO2 during thermal decomposition than 1.0 ZB-IFR/POM,indicating that ZB addition can effectively hinder full combustion of flame-retardant composites,exhibiting good synergistic flame-retardant effects.