Flame Retardant and Mechanical Properties of a Novel P-containing High Temperature Nylon Composites

A novel phosphaphenanthrene oxide PN-DOPO, based on bridged 9,10-dihrdro-9-oxa-10-phosphaphenamhrene-10-oxide (DOPO) and acetophenone was synthesized and the structure of product was characterized by FT-IR,1H-NMR,31P-NMR and MS. Glass fiber reinforced high temperature polyamide (GFPA6T/FR) composites, was prepared by incorporating the product (PN-DOPO) and aluminum diethyl-hypophosphite (OP1230) incorporated as flame retardant additives, GFPA6T/FR samples were characterized and analyzed by vertical burning test (UL-94), cone calorimeter, TGA, SEM and dynamic mechanical analysis (DMA) test. The results show that the addition of PN-DOPO and OP1230 can reduce the combustion level. GFPA6T/PN-DOPO reaches FV-0 level when the amount of PN-DOPO is 17.5%(mass fraction). HRR and THR of GFPA6T/PN-DOPO decrease more significantly than those of GFPA6T/OP1230, residual amount of thermal degradation is higher and char forming is more obvious. The results of DMA show that FR promotes micro cross-linking with PA6T molecular chain, leading to the increase of the rigidity of matrix. The results show that PN-DOPO is more significant than OP1230 in improving the flame retardancy and maintaining mechanical properties of GFPA6T.