The characterization of DOPO/MMT nanocompound and its effect on flame retardancy of epoxy resin

A DOPO-MMT nanocompound has been prepared and used to flame-retard epoxy resin (EP) compared with the physical mixture of DOPO and MMT. The structures of nanocompound and EP samples have been characterized by FTIR, XRD, SEM and TEM. Intercalated and exfoliation of MMT layers in DOPO and EP matrix have been observed which means good dispersity. The flame retardancy of EPs has been studied by limiting oxygen index measurements, UL-94 testing, and cone calorimeter test. The DOPO-MMT nanocompound shows better flame retardancy (limiting oxygen index, UL-94, peak of heat release rate, etc.) than the physical mixture of DOPO and MMT. The morphologies of EPs and chars after cone calorimeter test have been studied by SEM. Lighter color and better transparency of EP samples, smoother and less porous structure of chars both prove the DOPO-MMT nanocompound shows better flame retardancy because of the better dispersity of MMT layers in EP matrix.