2-Ethy-4-methylimidazole terminated polyurethane prepolymer as functional latent curing agents for epoxy resin crosslinking

Abstract

Three kinds of 2-ethyl-4-methylimidazole (EMI)-terminated polyurethane prepolymer were prepared through the reaction between diethylene glycol (DEG), polyethylene glycol 400 (PEG-400) and different isocyanates (toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), hexamethylenediisocyanate (HDI)). The storage stability, curing temperature and curing time of diglycidyl ether of bisphenol A (DGEBA) with EMI derivatives have been investigated by viscometer, DSC, and FTIR, respectively. It was proved that DGEBA/EMI derivatives exhibited superior storage stability than that of DGEBA/EMI. And the DGEBA can be effectively cured by the EMI derivatives at 120–140 °C without the generation of harmful species. Moreover, the higher impact strength and lower glass transition temperature (Tg) suggested an improvement of stiffness. The results of tensile test and TGA indicated that the excellent bonding strength with steel and unconspicuous compromise in thermal stability were simultaneously achieved.

Keywords:

• Latent curing agents
• polyurethane prepolymer
• epoxy resin
• storage stability
• viscosity and viscoelasticity

Additional information

Funding

This research was supported by the Science and Technology Projects of Guangdong province (2014A010105018) and the Science and Technology Projects of Zhaoqing City (2015B010902010).