A novel phosphorus/nitrogen‐containing flame retardant (DOPO‐AM) was synthesized by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and acrylamide (AM) and its chemical structure was characterized. DOPO‐AM was added into diglycidyl ether of bisphenol‐A (DGEBA) with curing agent m‐xylylenediamine (MXDA)to prepare flame retarded epoxy resin to reduce the possibility of fire. The compounds with different valences sulfur respectively replace partial DGEBA resin to study the effects of sulfur valences on the flame retardance of epoxy resins. The results indicated that DOPO‐AM had excellent flame retardance for epoxy resin. When phosphorus content was only 0.75%, DGEBS resin containing DOPO‐AM achieved the limiting oxygen index value of 34.55% and vertical burning test (UL‐94) V‐0 rating. Although sulfur element is help for refractive index of epoxy resin, sulfur element in three kinds of valences all weaken the flame retardant of epoxy resin. Improving phosphorus content is help for the synergistic effect of PN and PNS. Moreover, the flame retardance is not proportional to sulfur valence, sulfide with +2 valence had the best flame retardance. However, +6 valence sulfonic with strong oxidation effect worsen the flame retardant. Simultaneous thermal analysis of thermogravimetric analyzer and differential scanning calorimeter and scanning electronic microscopy photographs verified the above conclusion.

中文翻译：

---

不同价态硫对发光二极管环氧树脂阻燃性的影响

由9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物（DOPO）和丙烯酰胺（AM）合成了一种新型的含磷/氮阻燃剂（DOPO-AM），并对其化学结构进行了表征。将DOPO‐AM与固化剂m一起添加到双酚A（DGEBA）的二缩水甘油醚中苯二甲胺（MXDA）用于制备阻燃环氧树脂以减少起火的可能性。不同价态硫的化合物分别代替部分DGEBA树脂，以研究硫价对环氧树脂阻燃性的影响。结果表明，DOPO‐AM具有优异的环氧树脂阻燃性。当磷含量仅为0.75％时，含DOPO‐AM的DGEBS树脂的极限氧指数值为34.55％，垂直燃烧测试（UL‐94）V-0等级。尽管硫元素有助于提高环氧树脂的折射率，但三种价态的硫元素都会削弱环氧树脂的阻燃性。提高磷含量为P的协同效应帮助的N和P  Ñ S.此外，阻燃性与硫价不成比例，具有+2价的硫化物具有最佳阻燃性。但是，具有强氧化作用的+6价磺酸使阻燃性变差。热重分析仪和差示扫描量热仪的同时热分析以及扫描电子显微镜照片证实了以上结论。