Highly Effective P–P Synergy of a Novel DOPO-Based Flame Retardant for Epoxy Resin

Abstract

A novel flame retardant (FR) DOPO-PEPA, which was synthesized via Atherton–Todd reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 1-oxo-4-hydroxymethyl-2,6,7-trioxa-l-phosphabicyclo[2.2.2]­octane (PEPA), was used as an additive-type FR in epoxy resin (EP). The results of the limiting oxygen index (LOI), vertical burning test, and cone calorimeter test indicated that the flame retardance of FR-EP composites is dependent on the chemical structure of phosphorus-based FRs. EP/DOPO-PEPA shows pretty good mechanical properties and a relatively high degree of cross-linking. Furthermore, the synergy as DOPO-PEPA was more efficient than that of DOPO or PEPA alone to flame retardant EP. When the FR additives were 9.1%, the EP/DOPO-PEPA acquired a LOI value of 35%, UL94 V-0 rating, and the lowest peak of heat release rate (PHRR) of 595 kW/m2. Furthermore, its continuous and firm char residue layer also reinforced this kind of action.

Flame‐retardant performance and mechanism of epoxy thermosets modified with a novel reactive flame retardant containing phosphorus, nitrogen, and sulfur

“…In recent years, phosphorus‐containing flame retardants have been recognized as effective agents for the preparation of halogen‐free flame‐retardant EPs . Among these, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and its derivatives have been extensively employed to endow EPs with flame retardancy because of their high flame‐retardant efficiency, thermal stability, and applicability in EPs . However, an ideal flame‐retardant performance is only obtained under high phosphorus content when DOPO is used alone, which results in bioaccumulation of phosphorus and a sharp decline in glass transition temperature ( T g ) .…”

Synthesis of a caged bicyclic phosphates derived anhydride and its performance as a flame‐retardant curing agent for epoxy resins

“…Epoxy resins (EPs) are extensively applied as advanced composite materials in many areas due to their low shrinkage during the cure process, high mechanical properties, chemical resistance, and adhesion to substrates . Statistics showed that the annual output production of EPs was able to attain 3 million tons at the end of 2017, and it will carry a high growing trend in recent years.…”

Flame retardancy of epoxy resin nanocomposite with a novel polymeric nanoflame retardant

“…Epoxy resin (EP) is a critical and low‐cost thermosetting resin with excellent mechanical, heat resistance, and solvent resistance properties, which is widely used in coatings, adhesives, electrical and electronic materials, laminates, etc . However, the flammability of EP limits its application in some areas with high safety requirements .…”

“…Epoxy resin (EP) is a critical and low‐cost thermosetting resin with excellent mechanical, heat resistance, and solvent resistance properties, which is widely used in coatings, adhesives, electrical and electronic materials, laminates, etc . However, the flammability of EP limits its application in some areas with high safety requirements . The bromine‐containing flame retardant (FR) is one of the most effective FRs for EP and other polymeric materials, but there is potential toxicity to affect the health and environment in terms of the halogen‐containing micromolecule FR; 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), polyhedral oligomeric silsesquioxane (POSS), carbon nanotubes (CNTs), graphene/graphene oxide, etc have been used to flame retard EP matrix, and they have achieved good FR effect.…”