Study on a novel epoxy-terminated dendritic modifier as an active toughening agent for epoxy resin

Although significant efforts have been undertaken to explore the toughening of epoxy resins, it remains challenges to establish a simple and effective toughening technique which does not compromise its strength, thermal stability and processing performance. In this paper, toluene-diisocyanate-trimer (TDI-T) was utilized to manufacture a novel epoxy-terminated dendritic modifier TDI-T glycol diglycidyl ether (TDI-T GLDE). When the addition of TDI-T GLDE reaches 20% of the resin mass, the tensile strength, tensile elongation, compressive strength and impact strength were increased by 28.1%, 75%, 24.8%, and 138.0% respectively, compared to E-51. The thermal properties of the samples have been improved, including an increased glass transition temperature (Tg) from 68.2 to 73.2°C, as well as an increase in the initial decomposition temperature from 240.6 to 257.7°C. The toughening mechanism of TDI-T GLDE was studied through a combination of mechanical performance tests, thermal performance tests, and resin fracture surface morphology analysis.