Flame retardancy and thermal properties of organoclay and phosphorous compound synergistically modified epoxy resin

Phosphorous flame retardants (PFRs) are common halogen-free flame retardants. However, the flame retardancy of PFRs has not been fully exploited. Herein, the synergistic flame retardant effect of a typical phosphorous compound, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and organoclay on epoxy is studied. Results show that the peak of heat release rate (pHRR) and smoke production rate of modified epoxy resin (EP) with both 2.0 wt % phosphorus and 4.0 wt % organoclay are only 40% and 46% of that of neat EP resin, respectively, while the sole use of 2.0 wt % phosphorus only decrease the pHRR to 59% of that of neat EP resin. The structure and thermal decomposition behavior of as-prepared nanocomposites are analyzed, and a synergistic flame retardant mechanism is proposed. This investigation opens a new approach to obtain halogen-free EPs with higher flame retardancy and better overall properties than the EPs loaded with DOPO only. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43367.