Study of green epoxy resins derived from renewable cinnamic acid and dipentene: synthesis, curing and properties

Abstract

An epoxy based on cinnamic acid (Cin-epoxy) and an anhydride curing agent based on dipentene were prepared. Both products are liquids of low viscosity at room temperature. For the synthesis of the epoxy, cinnamic acid was first converted to a diacid by reacting with maleic anhydride via Friedel-Crafts reaction, followed by allylation of the carboxylic groups and subsequent epoxidation of the allyl double bonds. The curing agent was the Diels-Alder adduct of dipentene and maleic anhydride (DPMA). The chemical structures of Cin-epoxy and DPMA were confirmed by 1 H NMR, 13 C NMR, FT-IR and ESI-MS.Non-isothermal curing of Cin-epoxy was studied using differential scanning calorimetry (DSC). In addition to DPMA, two commercial anhydrides were also used to cure Cin-epoxy and the curing reactivity and properties of cured resins were compared. Thermal mechanical properties and thermal stability of the cured epoxy resins were studied using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), respectively. Results showed that Cin-epoxy was slightly more reactive than the bisphenol A type epoxy DER 332 and displayed good dynamic mechanical properties and thermal stability.

Biobased epoxy thermosets from vanillin-derived oligomers

“…1 16 were attributed to the glycerol ether repeating unit, which confirmed the oligomerization. Signal 17 was attributed to the proton of the hydroxyl moiety formed upon oxirane ring opening.…”

“…Another strategy found in the literature consists in synthesizing aromatic epoxy monomers from various biobased aromatic molecules such as furans [13,14], 4-hydroxybenzoic acid [15], cinnamic acid [16], catechin [11,17], gallic acid [18], eugenol [19], vanillic acid [20] and vanillin [21][22][23]. Among them, vanillin and derivatives are especially interesting as vanillin is the only monoaromatic compound currently industrially produced from lignin [24].…”

Preparation and properties of hydrogels based on PEG and isosorbide building blocks with phosphate linkages

“…5). This level of curing activation energy is significantly lower than that of the reaction of epoxy with amine [29] or anhydride [30][31][32] type curing agents, suggesting that the P-OH groups of phosphoester is more reactive when reacting with epoxies. The curing kinetics of IDE with PEGP was also examined using a parallel rheometer.…”

Developing Vegetable Oil-Based High Performance Thermosetting Resins

“…Several biobased epoxies based on renewable rigid chemicals, such as isosorbides (26), gallic acids (27) and catechins (28)(29)(30), were reported in the literature, which displayed comparable performances to that of the DGEBA type epoxies. However, these renewable chemicals are relatively expensive.…”