Morphology, thermal properties, and fire behavior of epoxy resin nanocomposites containing octaammonium polyhedral oligomeric silsesquioxane-modified montmorillonite

A series of epoxy resin (EP) nanocomposites containing octaammonium polyhedral oligomeric silsesquioxane-modified montmorillonite (OAPOSS-MMT) was prepared via in situ polymerization using 4,4-diaminodiphenyl sulfone as the curing agent. X-Ray diffraction and transmission electron microscopy were used to characterize the morphology of the resulting nanocomposites. Characterization results indicated the formation of intercalated and exfoliated structures. Thermogravimetric analysis (TGA) was performed to study the thermal properties of epoxy nanocomposites. Analysis results revealed that OAPOSS-MMT improved the thermal stability of EP matrix. TGA coupled with Fourier transform infrared spectrometry was used to detect pyrolytic gases. The gas species produced by epoxy nanocomposites were the same as those of control EP. A cone calorimeter was used to evaluate the flame retardancy of epoxy nanocomposites containing different concentrations of OAPOSS-MMT. Results showed that OAPOSS-MMT improved the flame retardancy of EP to some extent. The enhanced thermal oxidative stability was also confirmed by the data obtained through x-ray photoelectron spectroscopy.