Epoxy polymer toughening using dendritic spherulites microstructure formed by the self-assembly of alkyl branched tri-carbamates with a spacer of isocyanurate ring

Abstract

Currently, it remains a challenge to effectively improve the toughness of epoxy polymer without impairing the processability and other properties. Herein, a novel strategy was proposed for toughening epoxy polymer using the ordered microstructure formed by the self-assembly of C8H17-alkyl branched tri-carbamates with a spacer of isocyanurate ring at relatively low concentrations in the epoxy/amine system. The employed tri-carbamates slightly affects the viscosity of the modified epoxy due to its low molecular weight and melting behavior. The dendritic spherulites microstructures self-assembled in epoxy matrix through the desired molecular interactions between branched alkyl chains, –NHCOO– and CO act as the toughening materials that absorb fracture energy and subsequently improve the impact resistance of cured epoxy without significantly sacrificing Tg and mechanic strength. Moreover, due to the good plasticization of branched C8H17- chains and excellent mechanic strength of isocyanurate ring, in-situ dispersing tri-carbamates endows the modified epoxy the balanced cured properties.