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

Abstract

AbstractA 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 A novel flame‐retardant (MSD) was synthesized. MSD endowed EP with excellent fire safety and improved mechanical properties. MSD shortened solidification time of EP during preparation. MSD plays a flame‐retardant role in both condensed and gaseous phases.