Reactive phosphaphenanthrene aromatic ether diamine endowing epoxy resin with excellent fire resistance, liquid oxygen compatibility and cryogenic mechanical properties

摘要

? 2023 Elsevier B.V.Endowing conventional epoxy resin (EP) with great liquid oxygen compatibility (LOC) and desirable ultra-low-temperature mechanical property is essential to the applications in fields of cryogenic engineering. A reactive phosphaphenanthrene aromatic ether diamine (PBAH) flame retardant including phosphorus and nitrogen elements was synthesized by a simple one-pot reaction between HB (salicylaldehyde), DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and BAPP (2,2-bis[4-(4-aminophenoxy)phenyl]propane), then utilized to modify EP/BCI (biscitraconimide resin) system as a multifunctional component in this study. The resultant EP represented improved heat stability; outstanding fire resistance with an improvement of limiting oxygen index (LOI) value of 31.7% and V-0 rating in UL-94 test, as well as the desirable LOC and enhanced mechanical properties. The tensile strength (130.49 MPa) and fracture toughness (2.93 MPa·m1/2) increased by 51.3% and 78.7%, respectively, and the bending strength (255.30 MPa) increased by 116.8% than that of pure EP at cryogenic (77 K). All these results demonstrated the reactive PBAH showed a broaden potential in ultra-low-temperature engineering fields.