Eugenol-based benzoxazine: from straight synthesis to taming of the network properties

Abstract

Mixed benzoxazine precursors were synthesized using a blend of eugenol, a natural renewable product, and phenol. The structures of 15 these mixed benzoxazine precursors with different phenol:eugenol compositions were attested by 1 H NMR. Their polymerization and degradation were investigated and monitored by DSC and TGA and showed an enhancement of the crosslinking ability with the phenol content. Depending on its relative content, the phenol moiety proved to limit the thermal degradation of the bis-benzoxazine "hybrid" monomer and allowed the formation of crosslinked networks with high thermomechanical stabilities. The properties of the networks were closely dependent on the phenol : eugenol ratio, which allowed for an adjustment of the crosslinking density and a fine tuning of the 20 glass transition temperature (T g ) within a wide temperature range. A comparison between the polymerized hybrid precursors and blend of two pure monomers displaying the same overall composition showed the same material properties increasing the tune-ability of the system. The eugenol/phenol combination for the preparation of mixed/hybrid benzoxazines or corresponding blends clearly paves the way to new sustainable high performance bio-based materials. 25

Biobased Benzoxazine Derived from Daidzein and Furfurylamine: Microwave‐Assisted Synthesis and Thermal Properties Investigation

“…[15] Up to now,alarge quantity of biobased benzoxazines have already been prepared from the renewable cardanol, [16,17] diphenolic acid, [18,19] phloretic acid, [20] furfurylamine, [21,22] stearylamine, [23] coumarin, [24,25] umbelliferone, [26] and more recently the lignin derivatives (guaiacol, [27][28][29][30] vanillin, [31][32][33] and eugenol [34][35][36][37][38] ). [15] Up to now,alarge quantity of biobased benzoxazines have already been prepared from the renewable cardanol, [16,17] diphenolic acid, [18,19] phloretic acid, [20] furfurylamine, [21,22] stearylamine, [23] coumarin, [24,25] umbelliferone, [26] and more recently the lignin derivatives (guaiacol, [27][28][29][30] vanillin, [31][32][33] and eugenol [34][35][36]…”

“…Indeed, daidzein has been widely used in the food and pharmacy industry,d ue to itsv ariety of biologicala ctivity,s uch as antibacterial, antioxidation, and anti-inflammatory properties. [37] Recently,w ith the help of microwave-assisted heating under solvent-free conditions, Lomonacoe tal. [26] Furfurylamine is another biobased product derived from av ariety of agricultural byproducts such as corncobs and wheat bran.…”

High‐Performance Bio‐Based Benzoxazines from Enzymatic Synthesis of Diphenols

“…As aromatic compounds including phenolic derivates are the second most abundant class of organic compounds in nature representing about 25% of the earth's biomass, quite a large number of renewable phenol derivatives have been tested in recent years to synthesize benzoxazine precursors such as diphenolic acid, cardanol, vanillin, eugenol, chavicol, guaiacol, “lignin‐like” naturally occurring phenolic compounds (coumaric acid, ferulic acid, and phloretic acid), umbelliferone, arbutin, urushiol, catechol, etc. A special interest is focused on difunctional benzoxazine structure because it leads to cross‐linking.…”

“…Nevertheless, although biomass offers a wide range of phenolic compounds, many are ortho‐substituted with a methoxy group leading to benzoxazine precursor configurations that are not favorable to the formation of the cross‐linked network required to achieve high performance. To tackle this issue Dumas et al proposed a strategy for eugenol‐based benzoxazine which consists in substituting parts of ortho‐hindered eugenol moieties with free ortho ‐phenol moieties thus leading to precursors bearing mixed moieties and exhibiting an increased number of available reactive sites. This method was further adapted by Puchot et al to vanillin‐based benzoxazine and generalized under the name of “asymmetric benzoxazine precursor synthesis” .…”

Bio‐based aromatic copoly(ether ester)s with enhanced toughness and degradability: Influence of insertion of phenoxy‐ether linkage and eugenol‐derived composition on properties

“…24 Hereinto, the eugenol-based composition allows for the fine tuning of cross-linking density and T g values. The eugenol-based polybenzoxazine resins prompt the development of novel sustainable high-performance thermosets apart from epoxy and phenolic resins.…”