Flame Retardant Effect of Polyhedral Oligomeric Silsesquioxane and Triglycidyl Isocyanurate on Glass Fibre-Reinforced Epoxy Composites

Polyhedral oligomeric silsesquioxane (POSS) and triglycidyl isocyanurate (TGIC) were added to an aerospace grade epoxy resin (EP) individually or in combinations at low concentrations. The EP samples containing additives were cast into resin laminates and also used to produce glass fibre-reinforced composite laminates. The flammability of the two types of laminates was studied by limiting oxygen index, UL-94 and cone calorimetry. The cone results indicated that the use of POSS (10 wt%) in EP can significantly decrease resin/composite's peak heat release rate, total heat release, and CO production. The mechanical performance in flexural modes of the fibre-reinforced composite laminates was not adversely affected by the addition of POSS and TGIC in the resin. POSS containing samples had better retention of mechanical properties after exposure to radiant heat in a cone calorimeter compared with other samples. The results of thermogravimetry (TG), TG-FTIR, and dynamic FTIR indicated that the thermal degradation behavior of the EP is significantly changed by the addition of POSS. POSS can get grafted on the EP's main chain during earlier stages of decomposition and form a stable char layer to protect the underlying material from further decomposition. POLYM. COMPOS., 32:378-389, 2011. (C) 2010 Society of Plastics Engineers