High performance flame-retardant organic–inorganic hybrid epoxy composites with POSS and DOPO-based co-curing agent

Polyhedral oligomeric silsesquioxane (POSS) and a highly effective 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based flame retardant co-curing agent (D-bp) were chemically introduced into the 4,4′-diaminodiphenyl methane (DDM)/diglycidyl ether of bisphenol A (DGEBA) epoxy system to create organic–inorganic hybrid epoxy composites with simultaneously improved flame retardancy and mechanical properties. The results revealed that POSS/D-bp/DGEBA hybrid composites exhibited excellent comprehensive performance, in which the V-0 criterion of the UL-94 test was passed and the peak of heat release rate (P-HRR) was significantly decreased from 939 to 371 kW m−2 when the phosphorus content was only 0.25 wt%. The glass transition temperature (Tg) increased by 16.2 °C and obvious improvement in the mechanical properties was also evidenced.