Flame retardant epoxy resin based on organic titanate and polyhedral oligomeric silsesquioxane-containing additives with synergistic effects

Abstract

In order to develop a new epoxy resin (EP) possessing good thermal and mechanical properties as well as flame retardancy performance, the compound POSS-bisDOPO consisting of one polyhedral oligomeric silsesquioxane (POSS) and two unit of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) was synthesized and used as co-additive with tetrabutyl titanate to construct a phosphorous–silicon–titanium synergy system. Compared to pure EP, the char yields of the EP composites were increased. The LOI value and UL-94 ratings of the EP composite with a loading of 5% POSS-bisDOPO reached 31.0% and V-0 grade, respectively. The PHRR and THR reduced to 28.4 W g⁻¹ and 1.7 kJ g⁻¹. SEM results indicated that the char of the EP composites had an alveolate inner layer and continual compact outer layer, which was conducive to form effectively physical barrier to hinder the penetrating of oxygen and heat. DMA and three-point bending test results showed the mechanical property of the EP composites had no decline.