DOPO基低聚物与介孔二氧化硅协同阻燃环氧树脂

采用介孔二氧化硅(MS)与9,10–二氢–9–氧杂–10–磷杂菲–10–氧化物基低聚物(PDAP)对环氧树脂(EP)进行阻燃,制备阻燃环氧固化物。通过热重分析、极限氧指数(LOI)和UL–94测试对固化物的热稳定性和阻燃性能进行研究,并利用红外光谱、裂解–气相色谱/质谱联用仪和扫描电子显微镜对MS与PDAP的协同阻燃机理进行研究。结果表明,PDAP与MS存在较好的协同阻燃作用,当4%的PDAP和0.5%的MS添加至EP中,得到的固化物在燃烧时出现剧烈的吹熄现象,其LOI值高达34.3%,并通过UL–94的V–0级测试。在凝聚相,PDAP降解产生的磷酸类物质与MS反应生成磷硅酸盐,促进生成富磷、硅的致密炭层。在气相的阻燃机理主要是含磷自由基的猝灭作用和难燃气体的稀释作用。

Synergistic Effect of DOPO Based Oligomer and Mesoporous Silica on Flame Retardancy of Epoxy Resin

The mesoporous silica (MS),combined with DOPO-based oligomer (PDAP),were used to improve the flame retardancy of epoxy resin. The thermal stabilities and flame-retardant properties of epoxy thermosets were investigated by thermogravimetric analysis,limiting oxygen index (LOI) and UL–94 tests. Moreover,theflame-retardant synergism of MS and PDAP was studied by FTIR,Py-GC/MS and SEM. The results revealed that there was synergisticflame-retardant effect between MS and PDAP. When 4% PDAP and 0.5% MS were introduced into epoxy resin,the corresponding thermoset showed intense blowing-out effect during combustion,and achieved an LOI value of 34.3% and V–0 rating in UL–94 test. In the condensed phase, the phosphorus-based acids from the degradation of PDAP possibly reacted with MS to form silicophosphate,which could promote the formation of phosphorus-and silicon-rich char layer. In the gas phase,the flame-retardant mechanism was ascribed to the quenching effect of phosphorus-based radicals and diluting effect of nonflammable gases.