Effect of cyanate ester on the cure behavior and thermal stability of epoxy resin

Abstract

Epoxy resin (diglycidyl ether of bisphenol A, DGEBA)/cyanate ester mixtures were cured with a curing agent, 4,4-diaminodiphenylsulfone, and the effect of cyanate ester resin on the cure behavior and thermal stability in the epoxy resin was investigated with a Fourier transform infrared spectrometer, a rheometer, a dynamic mechanical analyzer, and a thermogravimetric analyzer. Cure reactions in the epoxy/ cyanate ester mixture were faster than that of the neat epoxy system. The cure reaction was accelerated by increasing the cyanate ester resin component. Glass transition temperature and thermal stability in the cured resins were increased with increasing cyanate ester resin component. This may be caused by the increase of crosslinking density due to the polycyclotrimerization of the cyanate ester monomer to form triazine rings and the reaction of cyanate ester resin with the epoxy network.

In situ FTIR and DSC investigation on cure reaction of liquid aromatic dicyanate ester with different types of epoxy resin

“…Two major categories of epoxy resins are the cycloaliphatic epoxides and the more familiar glycidyl ethers. 6 A curing system of diglycidyl ether/dicyanate/diaminodiphenylsufone mixture was studied by Kim,6 in which several reactions are involved. Recently, various onium salts were used as latent catalysts to cure glycidyl ethers [1][2][3][4] and cycloaliphatic epoxides.…”

A cyanate ester/microcapsule system with low cure temperature and self-healing capacity

“…5a), and by the absorption peak at 1752 cm À1 in the FTIR spectrum of the interfacial region between CE and MCs in cured CE/DDS/MCs system (Fig. 5b) [3,42]. The oxazolidinone rings can increase fracture toughness [43,44].…”

“…For all samples, the absorption peaks at 1564 cm À1 and 1367 cm À1 in the FTIR spectra are attributed to the triazine ring [3]. For the interfacial region between CE and MCs in cured CE/DDS/MCs, the absorption peaks between 3710 cm À1 and 3090 cm À1 are attributed to ANH and AOH, the absorption peak at 1690 cm À1 is assigned to the stretching vibration of C@NH in imidocarbonate and isourea [42], the peak at 1640 cm À1 is attributed to the isourea [21], and the absorption peak near at 1615 cm À1 is attributed to imidocarbonate [40]. The epoxy resins released from MCs catalyze CE and react with AOCN group/triazine rings to form aliphatic oxazolidinone rings.…”

“…As the temperature reaches 170°C, the storage moduli of the CE/MCs demonstrate a significant drop because of the lower stiffness of the MCs and the low molecular weight epoxy resin core materials. In addition, the drop in storage modulus can also be attributed to the flexible chains in the new networks formed by ÀOH, amine groups, epoxy groups and AOCN [3,21,[38][39][40][41][42][43][44], which have lower thermal stability. The two tan delta peaks (T g1 and T g2 ) of CE/MCs systems marked in Fig.…”

Moisture absorption modeling using design of experiments

“…The observed good resistance to moisture absorption of CE modified epoxy resin might be attributed to the formation of a higher crosslink density resin network when compared with that of the epoxy/PPO matrix. 3,12,13 For laminate A, both the temperaturehumidity interaction effect and the quadratic effect of temperature are significant at 1%. For laminate B, only the linear effects of temperature and humidity were found to be significant.…”