Metal‐coordinated epoxy polymers with suppressed combustibility. Preparation technology,thermal degradation,and combustibility test of new epoxy‐amine polymers containing the curing agent with chelated copper(II) carbonate

The diethylenetriamine chelate complex of copper(II) carbonate—DETA‐CuCO₃ (a fire retardant hardener of epoxy resins)—and the CuCO₃‐containing epoxy‐amine polymers—DGEBA/DETA‐CuCO₃(6), DGEBA/DETA‐CuCO₃(12), DGEBA/DETA‐CuCO₃(40), and DGEBA/DETA‐CuCO₃(80) with suppressed combustibility—have been obtained in the DETA‐DGEBA‐CuCO₃ system (DETA and DGEBA are diethylenetriamine and bisphenol A diglycidyl ether, respectively). The DETA‐CuCO₃ chelate complex was characterized by X‐ray powder diffraction, infrared spectra, and thermal analysis. The thermal gravimetric analysis results have revealed that thermal destruction of DETA‐CuCO₃ was finished at 400°С, and the maximal temperature of the combustion gases amounted to 520°С. The thermal behavior and combustibility of the CuCO₃‐containing epoxy‐amine polymers were studied using thermal analysis and “Ceramic tube” (CT) method. Thermal gravimetric analysis confirms that incorporation of the DETA‐CuCO₃ into DGEBA appreciably heightens the thermal stability and antiflammability of the CuCO₃‐containing epoxy‐amine polymers. Results of CT measurement reveal that maximal temperature of the combustion gases under burning of the DGEBA/DETA‐CuCO₃(12) sample in comparison with unmodified epoxy‐amine polymer (DGEBA/DETA) is lowered on 219°С and the loss of weight is decreased on 20.5 wt%. According to ASTM 635‐14, ASTM D2863‐13, and ASTM D1929‐16, the flame propagation rate, limiting oxygen index, and temperatures of ignition and self‐ignition have been measured for the elaborated polymer samples.