Dendritic organic–inorganic hybrid polyphenol and branched benzoxazine monomers with low curing temperature

Abstract

A novel dendritic organic–inorganic hybrid polyphenol (T2) based on cyclotriphosphazene was synthesized by the condensation reaction of T1 and phenol catalysed by phosphotungstic acid. The dendritic polyphenol T2 comprising twelve phenolic hydroxyl groups exhibited excellent solubility in common organic solvents. Three branched benzoxazine monomers with different oxazine ring content were synthesized via Mannich condensation reaction. These branched benzoxazine monomers showed low initial curing temperature. The properties of corresponding polybenzoxazines, such as thermal stabilities, mechanical properties, dielectric properties and gel contents significantly depended on the oxazine ring content of T3. With the increase of the oxazine ring content for T3, these properties could be greatly improved due to their high crosslinking density.