New Reactive Isoeugenol Based Phosphate Flame Retardant: Toward Green Epoxy Resins

Abstract

A bio-based reactive phosphate flame retardant derived from iso-eugenol was synthesized and fully characterized (1 H, 13 C, 31 P NMR, FTIR, MS) with the aim of improving flame retardancy behavior of bio-based epoxy thermosets. This new green flame retardant, diepoxy-iso-eugenol phenylphosphate (DEpiEPP) was then copolymerized either with conventional diglycidylether of bisphenol A resin (DGEBA) or with a totally bio-based glycidylether epoxy iso-eugenol (GEEpiE) resin using a bio-based camphoric anhydride (CA) as hardener. Resulting thermosets with varying rates of flame retardant (1.0 to 4.3 w% phosphorus) were then characterized (FTIR, DSC, nanoindentation, 3-point bending test, TGA, PCFC, cone calorimeter). By this way, a new solution was proposed allowing (i) to increase the bio-based content of thermosets (ii) to improve the flame retardancy properties by a reactive way and (iii) to provide epoxy thermosets with high Tg, excellent mechanical properties and a curing temperature compatible with the use of vegetable fibers. For instance, with a weight content of 2.0 w% P, both GEEpiE-CA-DEpiEPP (95% bio-based content) and partially bio-based DGEBA-CA-DEpiEPP (57% bio-based content) epoxy thermosets possess high Tg (respectively 129 and 105°C), bending elastic modulus and strength of respectively 4.08 GPa and 90 MPa and demonstrate good flameretardant properties due to char promotion showing high promise for application.

New Eco-Friendly Synthesized Thermosets from Isoeugenol-Based Epoxy Resins

“…For the matrix, it comes down to specific thermomechanical properties as well as specific rheological behaviour and a good affinity with the used fibers. Previous works [23] have demonstrated the ability of such thermoset systems to fulfil the requirements for structural composite applications, with high elastic properties and bending strength, high Tg and good flame-retardant properties (when using phosphate-based derivatives from isoeugenol). Nevertheless, GEEpiE synthesis needs a purification by chromatography on a silica column, which is time consuming and not environment-friendly.…”

Fire-Safe Polymer Composites: Flame-Retardant Effect of Nanofillers

“…In some specific flame retardants, promotional effects occur when combinations of P-N, P-Si, and N-Si compounds are used [ 112 , 115 , 116 , 117 , 118 , 119 ]. In many cases, the use of reactive co-monomers is preferred since epoxy resins flame-retarded with conventional additives have poorer physical properties than unmodified ones [ 120 , 121 , 122 , 123 , 124 , 125 ]. Despite their shortcomings, laminated flame retardants dominate the market because most of the available reactive solutions are too complex and expensive.…”

Eugenol, a developing asset in biobased epoxy resins

“…Diglycidyl 55,56 or triglycidyl 57 phosphates based on eugenol or isoeugenol were presented successively.…”

“… eugenol 55 or iso-eugenol 56 based diglycidyl phosphate Zhao et al 55 and Boni et al 56 synthesized eugenol (A) or iso-eugenol (B) based diglycidyl phosphates by reaction between dichlorophenylphosphate and eugenol or iso-eugenol followed by epoxidation reaction with m-CPBA or oxone, respectively (Scheme 22). The diglycidyl monomers were formulated with either DDM or anhydrides with imidazole as catalyst.…”