含二羟基DOPO衍生物阻燃改性环氧树脂的制备与热性能研究

DOPO(9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物)、多聚甲醛、二乙醇胺为原料合成了含二羟基的DOPO衍生物DHDOPO,并作为反应型阻燃剂引入到环氧树脂分子链结构中,制备出一组不同含磷量的阻燃环氧树脂复合材料。采用极限氧指数(LOI)法和垂直燃烧(UL-94)法测试材料的燃烧性能,结果表明,在含磷量为1.5%时,氧指数达到35.0%,并达到V-0级别。锥形量热计(Cone)数据显示阻燃改性后的环氧树脂具有更低的热释放速率峰值(PHRR)和总热释放量(THR),说明具有更高的火灾安全性。此外,还通过热重分析(TGA)实验研究了DHDOPO对环氧树脂热稳定性能的影响。通过扫描电镜对燃烧过后的炭渣形貌进行分析,推测了燃烧的过程和阻燃的机理。

Preparation, flame retardancy and thermal properties of a dihydroxy-containing DOPO derivative modified epoxy thermosets

A dihydroxy-containing DOPO derivative (DHDOPO) has been synthesized by the reaction of DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), paraformaldehyde and diethanolamine, and used as a kind of reactive flame retardant for epoxy resin. Then a series of epoxy hybrids, which contain different phosphorus contents, were prepared. The flammability of epoxy hybrids was characterized by limiting oxygen index (LOI) and vertical burning test (UL-94). The results indicated that the EP sample which contains 1.5 wt% phosphorus content possesses LOI value as high as 35.0% and passes V-0 rating. The cone results showed that the modified epoxy resin has lower peak heat release rate (PHRR) and total heat release (THR), which suggest the higher fire safety performance. Moreover, the effect of DHDOPO on the thermal stability of epoxy resin was investigated by thermogravimetric analysis (TGA). The char residue after combustion was investigated by scanning electron microscopy (SEM). The burning process and flame retardant mechanism has also been inferred.