Epoxy networks possessing polyoxyethylene unites and loaded by Jeffamine-modified graphene oxide nanoplatelets

Abstract

In this study, three epoxy thermosetting materials possessing polyoxyethylene units are prepared starting from polyethylene glycol. To improve the mechanical strength of the epoxy materials, alongside the flexible units of polyoxyethylene, rigid aromatic and alicyclic moieties arised from two popular monomers are also present into the structures obtained. Thus, epoxide-functionalized polyoxyethylene (EFPOE) and/or diglycidyl ether of bisphenol A (DGEBA) are cured by amine-functionalized polyoxyethylene (AFPOE) and/or isophorone diamine (IPDA). The formulas of EFPOE:DGEBA/AFPOE:IPDA (A), EFPOE/IPDA (B), and DGEBA /AFPOE (C) are stoichiometrically used. To reinforce thermal and thermo-mechanical behaviors, three epoxy networks (D, E, and F) with the same formulas but loaded by 0.5 wt.% of Jeffamine-modified graphene oxide (GO) nanoplatelets are also prepared. In the binary epoxy-amine systems for preparing A and D networks, both resins and hardeners are taken in equimolar amounts. In other systems, leading to B, C, E and F networks, either resin or hardener, just one, is based on polyoxyethylene unites. Heat stability, ultimate tensile strength, elongation at break, and storage moduli (E' values) of the neat epoxy networks as well as the GO-loaded ones were measured and compared with each other. It was found that the epoxy/GO networks, especially that of prepared using binary epoxy-amine systems (network D), have superior thermal properties and greater values of storage modulus (E') around Tg and higher temperatures.