Architecture Study of a Reactive Flexible Polyamine as a Toughening Agent for Epoxy Resin

A novel approach to toughen epoxy resin with a liquid rubber is presented in this work. For this purpose, the highly reactive aliphatic amine-terminated polybutadiene (ATPB) was synthesized as an epoxy toughening agent. According to the mechanical test results, incorporation of ATPB into epoxy networks can significantly toughen the epoxy matrix. The addition of 10 phr ATPB increased the critical stress intensity factor (KIC) and critical strain energy release rate (GIC) of the epoxy from 0.85 to 2.16 MPa.m1/2 and from 0.38 to 3.02 kJ.m-2, respectively. The toughening and failure mechanisms were discussed based on the epoxy network morphological characteristics. The reduction in crosslinking density of the epoxy system upon modification was confirmed by dynamic mechanical analysis (DMA). This article opens up the possibility of utilizing reactive flexible diamines with polybutadiene backbone as effective toughening agents for thermoset polymer