Thiol-yne/thiol-epoxy hybrid crosslinked materials based on propargyl modified hyperbranched poly(ethyleneimine) and diglycidylether of bisphenol A resins

Abstract

A novel curing methodology based on the combination of thiol-yne and thiol-epoxy click reactions has been developed. The curing process consists of a first photoinitiated thiol-yne reaction, followed by a thermal thiol-epoxy process. As alkyne substrate a new propargyl terminated hyperbranched poly(ethyleneimine) (PEIyne) has been synthesized from the reaction of commercial poly(ethylenimine) (PEI) and glycidyl propargyl ether. The evolution of the curing of different mixtures of PEIyne and diglycidylether of bisphenol A (DGEBA) with the stoichiometric amount of tetrathiol (PETMP) has been monitored by DSC. The new hybrid materials have been characterized by thermomechanical analysis, thermogravimetry and by electronic microscopy inspection and compared with neat thiol-yne and thiol-epoxy materials. The T_gs of the complete cured materials increase with the proportion of epoxide in the formulation. The thiol-yne network improves the plasticity of the fracture of the materials.