Preparation and Properties of Polyether Aliphatic Polymerized Amide as a Vegetable Oil-Based Epoxy Curing Agent

An epoxy curing agent polyether aliphatic polymerized amide (PEAPA) was synthesized using epoxy fatty acid methyl ester and diethylenetriamine. The Fourier transform infrared spectra and ¹H NMR analysis indicated successful synthesis of PEAPA. Gel permeation chromatography showed a high degree of polymerization. The obtained PEAPA was used to cure E51 epoxy resin and partially replace rigid 1,3-cyclohexanediamine curing agent. A series of epoxy resins with varying rigidities were prepared. The mechanical and thermal properties of the materials were analyzed. Mechanical property tests showed that the tensile strength and hardness of the materials decreased gradually with increased PEAPA content. However, elongation at breaks of the prepared materials increased with increased PEAPA content. Micromorphological investigation indicated excellent compatibility between PEAPA and the curing system. Furthermore, a dynamic mechanical thermal analysis demonstrated that the glass transition temperature of the epoxy resin decreased with increased PEAPA content. Thermal stability, while still excellent, decreased slightly with the addition of PEAPA. At the primary weight loss stage, initial decomposition temperatures for all resins were above 330 °C.