A comprehensive study on the curing kinetics and network formation of cyanate ester resin/clay nanocomposites

A series of cyanate ester resin (CY)/exfoliated clay nanocomposites were prepared successfully. Curing kinetics and network formation of the nanocomposites of CY modified with a natural montmorillonite clay (Na+), a MT2EtOH (methyl, tallow, bis-2-hydroxyethyl, ternary ammonium) modified clay (30B) and a 2M2HT (dimethyl, dihydrogenated tallow, quaternary ammonium) modified clay (20A), were studied. The incorporation of the various clays showed different accelerating effects on the cure of CY, among which 30B clay showed the most pronounced effect. TEM images and XRD patterns confirmed that the 30B and Na+ clays were exfoliated in the CY matrix. FTIR results indicated that the clays reacted with the CY to form a coordination complex, with the coordination complex then being transformed to single bondOsingle bond(Cdouble bond; length as m-dashNH)single bondOsingle bond bonds during the curing reaction. The strong accelerating effect of these clays on the curing process of the CY appears due to the formation of the coordination complex. Raman spectra revealed that the CY resin preferentially reacted with the hydroxyl groups in the clays firstly to form the coordination complex, rather than reacting with itself to form the triazine rings, during the network formation of the CY/clay nanocomposites. The formation of the 3-dimensional network for CY/clay nanocomposites was delayed until the mid to late stages of the cure, as determined by the absence of the triazine rings.