磷酸酯双三聚氰胺盐阻燃环氧树脂的燃烧性能和阻燃机理

以季戊四醇、三氯氧磷、三聚氰胺为原料合成了1-氧-4-亚甲基-2,6,7-三氧-1-磷杂双环(2,2,2)辛烷]磷酸酯双三聚氰胺盐阻燃剂,将该阻燃剂加入到环氧树脂中制成阻燃环氧树脂。用TG、SEM、EDS和FT-IR进行表征,并采用极限氧指数法和垂直燃烧法测试材料的燃烧性能,结果表明,极限氧指数和垂直燃烧性能随阻燃剂含量的增加而提高,当阻燃剂含量达到30%时,氧指数达到36,垂直燃烧性能达到V-0级;阻燃剂对材料的成炭量影响不大,但改变了炭层的组成和物理性质,燃烧过程中形成的含有P、O、N的粘性高聚物将炭层连接在一起,起到了隔热、隔氧作用,发挥了凝聚相阻燃作用。此外,阻燃环氧树脂在燃烧过程中有NH3等不燃气体逸出,有效地稀释了气相中的氧气浓度,发挥了气相阻燃作用,对材料的阻燃有协同作用。

Combustion Behavior and Pyrolysis of Epoxy Resins Blended with Caged Bicyclic Dimelamine Phosphate

A novel flame retardant of dimelamine salts of 1-oxo-4-hydroxymethyl-2,6,7-trioxa-phosphabicyclo()octane-phosphate was synthesized from pentaerythritol,phosphorus oxychloride and melamine,which was combined into epoxy resins to obtain halogen-free flame retarded resins.Limiting oxygen index(LOI) and UL-94 test were used to characterize the flammability.Thermogravimetric analysis(TG),scan electronic microscopy(SEM),(energy) dispersive spectrometry(EDS),and fourier transform infrared(FT-IR) were carried out to investigate the pyrolysis of flame retarded resins,the structure and elements of char layers,and the changes of chemical species during heating process.The results show that the incorporation of the flame retardant(FR) greatly improves the flame retardancy of the epoxy resins.LOI of the resins increases with the increasing of the amount of the flame retardant,The quantities of char residues are similar for all epoxy resins with and without the flame retardant.However,the composition and structure of char layers are different.Char layers are integrated by viscous P,N,O-contained polymers due to the flame(retardant) pyrolysis,which acts as a physical barrier against heat transmission and oxygen diffusion,thus(reducing) the combustion of polymers.At the same time,uninflammable gas,such as NH_3 and H_2O,escape and dilute(oxygen,) playing a synergistic role on flame retardancy.