聚磷酸酯阻燃剂复配聚磷酸铵对环氧树脂阻燃性能的影响

合成了一种9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)的衍生物——聚苯氧基磷酸-2-10-氢-9-氧杂-磷杂菲基对苯二酚酯(POPP), 以间苯二胺(m-PDA)为固化剂, 环氧树脂(EP)为基料, POPP为阻燃剂, 复配聚磷酸铵(APP), 制备了不同磷含量的阻燃环氧树脂. 利用极限氧指数(LOI)和垂直燃烧(UL94)实验表征了环氧树脂的阻燃性能; 以热重分析、 锥型量热和扫描电镜分析了阻燃环氧树脂的热性能和表面形态. 研究结果表明, 阻燃剂总加入量(质量分数)为5%时即可达到UL94 V-0级, 同时LOI值为27.7%; 当总加入量为15%, 即w_POPP=5%, w_APP=10 %时, 其LOI值可达到33.8%. 随着磷含量的增加, 阻燃环氧树脂的初始降解温度略有降低, 但高温下的残炭率明显增加. POPP/APP的加入在很大程度上降低了环氧树脂的热释放速率、 有效燃烧热、 烟释放量和有毒气体释放量. 阻燃环氧树脂在高温下形成比较稳定的致密膨胀炭层, 为底层的环氧树脂主体隔绝了分解产物及热量和氧气交换, 增强了高温下的热稳定性.

Influence of Polyphosphate Flame Retardant Couple with Ammonium Polyphosphate on Epoxy Resin†

A novel polyphosphate flame retardant, poly ( 2-10-hydrogen-9-oxa-phosphaphenanthrene hydroquinone phenyl phosphate) (POPP), aimed at improving the flame retardancy of EP was prepared. POPP and ammonium polyphosphate(APP) at the mass ratio of 1:2 were added into EP to form a series of flame retardant modified epoxy resin( FR-EP ) . The chemical bond adsorptions of FR-EP were investigated by infrared spectroscopic analysis. The thermal stability was study by thermal gravimetric analysis( TGA) . Flame retardant properties as well as burning behavior of epoxy resin composites have been investigated by limited oxygen index ( LOI ) and vertical burning test ( UL-94 ) . Fire properties of modified epoxy resin were test by Cone calorimeter. The morphological characteristics of char residue after Cone test were studied by scanning electron microscope( SEM) . The result shows that POPP increase burning behavior at lower adding amount, which help epoxy resin to pass UL-94 V-0 at 5%. But POPP modified epoxy resin gave out only 24. 2% of LOI value. POPP/APP flame retardant increase not only UL-94 grade but also much higher LOI value. A UL-94 V-0 grade was obtained when 5% POPP/APP were added into the epoxy matrix and 27. 7% LOI value. When adding amount of POPP/APP are increased to 15%, a higher LOI value of 33. 8% can be get. Results of TGA test indicate that decomposition temperature of FR-EP decrease along with increase of flame retardant amount. But modified samples give out more char residue. By incorporation of POPP/APP, THR, HRR, EHC, TSR and COP of FR-EP were reduced obviously, and promote char residue dramatically. PkHRR decrease from 831. 5 kW/m2 to 346. 8 kW/m2 at 15% of adding amount. Morphology study shows that good flame retardant property of FR-EP is contributed to well-formed char residue structure. These structures of char are net-like and type may prevent little burning product from moving out to the surface of matrix. Moreover, this char residue protects inner material from heat.