含磷固化剂及固化环氧树脂的合成及表征

以4,4′-二氨基二苯基甲烷(DDM)、苯甲醛和亚磷酸二乙酯为原料,合成了两种含磷固化剂PM1和PM2,用红外光谱、核磁共振氢谱对PM1和PM2的结构进行了表征。用DDM,PM1,PM2分别固化双酚A型(DGEBA)环氧树脂,得到DGEBA-DDM,DGEBA-PM1,DGEBA-PM2树脂,采用示差扫描量热法、热重分析(TGA)和极限氧指数(LO I)对DGEBA-DDM,DGEBA-PM1,DGEBA-PM2树脂的玻璃化转变温度(Tg)、反应活性、热稳定性和阻燃性能进行了表征。实验结果表明,PM2的反应活性比PM1低;DGEBA-DDM,DGEBA-PM1,DGEBA-PM2树脂的Tg分别为178,112,145℃;TGA结果表明,700℃时DGEBA-PM1和DGEBA-PM2树脂的成炭率分别为29%和35%,而700℃时DGEBA-DDM树脂的成炭率只有19%;DGEBA-PM1和DGEBA-PM2树脂的LO I值由DGEBA-DDM树脂的24%分别增至30%和35%,且阻燃性能大幅度提高。

Synthesis and Characterization of Phosphorus-Containing Curing Agent and Cured Epoxy Resins

Phosphorus-containing curing agents(PM1 and PM2)for epoxy resins were synthesized from 4,4′-diamino-diphenyl-methane(DDM),benzaldehyde and diethyl phosphite.Their structures were characterized by means of IR and ~1H NMR.Diglycidyl ether of bisphenol A resin(DGEBA)was cured by using PM1,PM2 and DDM.DGEBA-PM1,DGEBA-PM2 and DGEBA-DDM resins were obtained.Glass transition temperature(T_g),reactivity,thermal stability and fire resistance properties of resins were investigated by means of DSC,thermogravimetric analysis(TGA)and limiting oxygen index(LOI)analysis.As curing agent,PM1 is more reactive than PM2.T_g values of DGEBA-PM1 and DGEBA-PM2 are 112℃ and 145℃,respectively,lower than that of DGEBA-DDM.TGA reveals that char yields of DGEBA-PM1 and DGEBA-PM2 resins are 29% and 35% at 700℃ respectively,whereas DGEBA-DDM resin is 19% at same temperature.LOI values of DGEBA-PM1 and DGEBA-PM2 resins are 30% and 35%,respectively.The high char yield and LOI indicate that inflaming-retardance of resins is greatly improved.