Low-flammability epoxy resins with short solidification time and good mechanical properties

A novel fire-resistant epoxy resin (EP) material has been prepared using EP, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), maleic anhydride, and 2-aminobenzothiazole. Maleithiazolephosphaphenanthrene (MSD) was synthesized and its chemical structure was characterized using infrared spectroscopy (IR) and nuclear magnetic resonance (NMR). Fire-resistant additive MSD was introduced into EP. The flammability and mechanical properties of the modified EP materials were then investigated using limiting oxygen index (LOI), UL-94 vertical burning, cone calorimeter (CC), tensile, three-point bending, and izod unnotched impact tests. EP blend containing 4%MSD displayed a UL-94 V-0 rating and an LOI value of 32.2%. Heat release and smoke release determined using cone calorimeter for the sample containing 4% MSD were lower than the sample of EP alone. Further, introduction of 4% MSD to EP material improved its izod impact, tensile strength, and flexural strength by 13.3%, 13.9%, and 21.6%, respectively. Inferences for the mode of fire-resistant action were available from MSD, XPS, SEM, Raman, and Py-GC/MS. MSD has a positive effect on fire resistance in both the condensed phase and gas phase. Highlights circle A novel flame-retardant (MSD) was synthesized. circle MSD endowed EP with excellent fire safety and improved mechanical properties. circle MSD shortened solidification time of EP during preparation. circle MSD plays a flame-retardant role in both condensed and gaseous phases.