Abstract
This work focused on the effects of chitosan (CS) and 9,10-dihydro-9-oxo-10-phosphaphenanthrene-10-oxide (DOPO) on the flammable propertied of epoxy resin matrix. The EP composites were fabricated by direct mixing method through a general curing method. The influence of CS, DOPO and CS / DOPO on the resin was investigated through cone calorimetry tests (CC), UL-94 vertical burning, limiting oxygen index (LOI), thermal gravimetric analyzer (TGA), differential scanning calorimeter (DSC) and thermogravimetric analyzer-Fourier infrared combined system (TG-FTIR). The char residues of modified EPs after CC tests were investigated by FTIR, EDX and XPS. Under the 10% addition of CS / DOPO in EP, with the mass ratio of CS and DOPO of 1 : 1, 1 : 2, 1 : 3, 2 : 1 and 3 : 1, the flame retardancy properties of EPs all increased, but only if EP/10% CS1/DOPO2 and EP/10% CS2/DOPO1 achieved a V-0 rating and their values of LOI were 33.7% and 32.5%, respectively. Compared with EP, the peak heat release rate, peak smoke produce rate and total heat release of EP/10% CS1/DOPO2 and EP/10% CS2/DOPO1 decreased, especially, total smoke release decreased by 61.9% and 71.0%, the char residuals amount increased by 84.3% and 41.6%, and the average CO2 yield decreased by 55.4% and 55.0%, respectively. It is worth nothing that the mechanical properties increased, especially the flexural strength increased by 36.0% and 38.4%, respectively. The results indicated that DOPO and CS had important synergistic effects for simultaneous increase both the flame retardancy and mechanical properties of EP composites.
Flame retardant epoxy resin based on organic titanate and polyhedral oligomeric silsesquioxane-containing additives with synergistic effects
