synthesis, curing behavior and thermal properties of a new series of epoxy-imide resins for powder coatings

The non-isothermal curing behavior of a new series of epoxy-imide resins based on trimellitimide (tmi) structures, synthesized in a three-step procedure, were evaluated by differential scanning calorimetry (dsc). the chemical structures of the synthesized intermediates and their corresponding epoxy-imide resins were characterized and confirmed by ftir and 1h-nmr spectroscopy. the synthesized epoxy-imide resins and a medium molecular weight commercial epoxy resin chs-130 (as reference) were cured by dicyandiamide (dicy) as curing agent. furthermore, the thermal stability of understudied systems was evaluated by thermogravimetric analysis (tga). the results showed that the determined melting temperatures of epoxy-imide resins were significantly higher than that of the reference one, ep4, but were still within the range of powder coating application temperatures. we also found that the glass transition temperatures of their cured systems were to a considerable extent higher compared with the ep4 system, ca. 138.2-162.7℃ vs. 102.2℃. the thermogravimetric data also showed that the cured epoxy-imide samples had lower degradation rates, extended stability windows, and enhanced flame retardancy compared with the reference resin.

Synthesis, Curing Behavior and Thermal Properties of a New Series of Epoxy-Imide Resins for Powder Coatings

The non-isothermal curing behavior of a new series of epoxy-imide resins based on trimellitimide (TMI) structures, synthesized in a three-step procedure, were evaluated by differential scanning calorimetry (DSC). The chemical structures of the synthesized intermediates and their corresponding epoxy-imide resins were characterized and confirmed by FTIR and 1H-NMR spectroscopy. The synthesized epoxy-imide resins and a medium molecular weight commercial epoxy resin CHS-130 (as reference) were cured by dicyandiamide (DICY) as curing agent. Furthermore, the thermal stability of understudied systems was evaluated by thermogravimetric analysis (TGA). The results showed that the determined melting temperatures of epoxy-imide resins were significantly higher than that of the reference one, EP4, but were still within the range of powder coating application temperatures. We also found that the glass transition temperatures of their cured systems were to a considerable extent higher compared with the EP4 system, ca. 138.2-162.7℃ vs. 102.2℃. The thermogravimetric data also showed that the cured epoxy-imide samples had lower degradation rates, extended stability windows, and enhanced flame retardancy compared with the reference resin.