Curing Behavior and Heat Resistance of Epoxy Resin Cured by Diamine with Heterocyclic Ring

摘要

Benzobisoxazole-containing diamine,2,6-Di(p-aminophenyl)benzo [1.2.5.4] bisox-azole (DIABO),was derived from diaminodihydroxybenzene dihydrochloride (DADHB-2HC1) and p-aminobenzoic acid (PABA) via condensation reaction.The structure of DIABO was confirmed through FTIR,~1H NMR,x-ray diffraction (XRD) and UV-Vis spectra,etc.The curing behavior of diglycidyl ether of bisphenol A (DGEBA) and DIABO as curing agent was investigated using differential scanning calorimetry (DSC).Dynamic kinetic parameters were calculated by using Kissinger's and Ozawa's methods,respectively.The glass transition temperatures of cured system,DGEBA/DIABO,DGEBA/DIABO/DDS (cured with mixtures of DIABO and diaminodiphenyl sulfone (DDS)) and DGEBA/DDS,were 213°C,193°C and 175°C,respectively,based on torsional braid analysis (TBA).The integral procedure decomposition temperatures (IPDT) were 885°C,734°C and 604°C,respectively.Char yields at 572°C were 39.82%,24.66% and 21.57%,respectively.Hydrothermal ageing of cured resins was also discussed.All results showed that DIABO as curing agent can remarkably improve the thermal and hydrothermal resistance of the cured epoxy resins.