纳米Al_(2)O_(3)磷杂菲改性环氧树脂的制备与阻燃耐温性能研究

Preparation of nano-Al_(2)O_(3) phosphaphenanthrene modified epoxy resin and research on its flame-retardant and temperature resistance

以9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)、对羟基苯甲醛、4,4′-二氨基二苯甲烷(DDM)为原料合成了新型磷杂菲阻燃固化剂DOPO-DDM;使用表面处理过的纳米Al_(2)O_(3)、DOPO-DDM和普通固化剂DDM作用于环氧树脂,研究改性前后环氧树脂的阻燃耐温性能。利用红外光谱(FT-IR)、差示量热(DSC)对DOPO-DDM的结构和固化条件进行表征分析;通过DSC、极限氧指数、垂直燃烧实验探究改性前后环氧固化物的热性能和阻燃性能;通过扫描电镜(SEM)观察燃烧实验后残炭形貌,研究其阻燃机制。结果表明:DOPO-DDM的加入会提升环氧固化物的阻燃性能,但同时会降低其热性能,在此基础上加入纳米Al_(2)O_(3)可以提高环氧固化物的耐温性。当纳米Al_(2)O_(3)添加质量为3%时,环氧固化物的玻璃化转变温度较未添加时提升13℃;用DOPO-DDM取代28%环氧当量的DDM时,LOI值为32.3%,UL-94测试等级达到V-0级。

A novel phosphaphenanthrene flame-retardant curing agent DOPO-DDM was synthesized from 9,10-dihydro-9-oxa-10-phosphoramidite 10-oxide(DOPO),p-hydroxybenzaldehyde and 4,4′-diaminodiphenylmethane(DDM).The surface-treated nano-Al_(2)O_(3),DOPO-DDM and common curing agent DDM were used to act on epoxy resin to study the flame retardancy and temperature resistance of the epoxy resin before and after modification.The structure and curing conditions of DOPO-DDM were characterized and analyzed by FT-IR and DSC;the thermal properties and flame-retardant properties of the epoxy cured products before and after modification were investigated by DSC,limiting oxygen index,and vertical combustion experiments.The morphology of the residual carbon after vertical combustion experiments was observed by SEM,and the flame-retardant mechanism was studied.The results showed that the addition of DOPO-DDM could improve the flame-retardant properties of the epoxy cured products,but at the same time reduced its thermal properties.On this basis,adding nano-Al_(2)O_(3) could improve the temperature resistance of the epoxy cured products.When the addition amount of nano-alumina was 3wt%,the glass transition temperature of the epoxy cured product was increased by 13℃compared with that without addition;when DOPO-DDM was used to replace DDM with 28%epoxy equivalent,the LOI value was 32.3%,and the UL-94 test grade reached V-0 level.