High‐toughness, environment‐friendly solid epoxy resins: Preparation, mechanical performance, curing behavior, and thermal properties

Abstract

ABSTRACTThe development of a facile and efficient approach to prepare high‐toughness epoxy resin is vital but has remained an enormous challenge. Herein, we have developed a high‐performance environment‐friendly solid epoxy resin modified with epoxidized hydroxyl‐terminated polybutadiene (EHTPB) via one‐step melt blending. The characterization, mechanical performance, curing behavior, and thermal properties of EHTPB‐modified epoxy resin were investigated. EHTPB‐modified epoxy resin exhibited excellent toughness with a 100% increase in elongation at break of tensile than that of neat epoxy resin. The transfer stress and dissipated energy in the rubber phase were predominant mechanisms of toughening. The toughening effect of EHTPB on solid epoxy resin was better than that of some of the previously reported liquid epoxy resins. Meanwhile, at 10 wt % of EHTPB loading, the EHTPB‐modified epoxy resin displayed high strength and 22 and 101% improvement of flexural strength and impact strength, respectively. Moreover, at 10 wt % of EHTPB loading, the activation energy of EHTPB‐modified epoxy resin for curing reaction decreased from 73.89 to 65.12 kJ·mol−1, which is beneficial for the curing reaction. Furthermore, EHTPB‐modified epoxy resin had a good thermal stability and the initial degradation temperature increased from 249 to 313 °C at 10 wt % of EHTPB loading. This work provides a simple‐preparation and highly efficient and large‐scale approach for the production of high‐toughness environment‐friendly solid epoxy resins. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48596.