三聚氰胺改性聚氨基环三磷腈对环氧树脂的阻燃作用

Flame Retardancy of Polyamidocyclotriphosphazene Modified with Melamine in Epoxy Resin

通过极限氧指数测定,垂直燃烧试验和锥形量热分析研究了三聚氰胺改性聚氨基环三磷腈(MPHACTPA)对改性脂肪胺固化环氧树脂(E-44/DG593)的阻燃作用,并与聚氨基环三磷腈(PHACTPA)进行了比较。结果表明,PHACTPA和MPHACTPA对E-44/DG593均有较好的阻燃作用。三聚氰胺与六氯环三磷腈的摩尔比对MPHACTPA的阻燃作用有些影响,当两者的摩尔比为1.5∶1(MPHACTPA-2)时,其阻燃作用最好。锥形量热试验残余物分析结果表明:PHACTPA和MPHACTPA在燃烧过程中受热分解成磷酸、偏磷酸、聚磷酸等,这些化合物促使E-44/GD731脱水炭化,并在NH3、N2、CO2等惰性气体的发泡作用下形成膨胀性炭层,因而产生强的凝聚相阻燃作用。MPHACTPA-2促进成炭的能力较强,因而阻燃作用更好。

The flame retardancy of polyamidocyclotriphosphazene modified with melamine （MPHACTPA） in epoxy resin cured with modified aliphatic amine（E-44/DG731） was studied by limiting oxygen index （LOI） measurement, vertical burning test and cone calorimeter test（CCT）, and compared with polyaminocyclotriphosphazene （PHACTPA）. The results reveal that PHACTPA and MPHACTPA have good flame retardancy in E-44/DG731. The mole ratio of melamine and hexachlorocyclotriphosphazene has some influence on the flame retardancy of MPHACTPA. When their mole ratio is 1.5∶1（MPHACTPA-2）,its flame retardancy is the best. The analysis of the residues obtained in CCT reveals that PHACTPA and MPHACTPA are decomposed into non-volatile phosphoric acid compounds in the process of combustion, which promote the charring of E-44/DG731, and the char is changed into the intumescent layer by the foaming of CO2, NH3 and N2 released from the decomposition of the composite. The above processes result in good condensed phase flame retardancy. The promoting char-forming ability of MPHACTPA-2 is stronger, so its flame retardancy is better.