Limonene-Based Epoxy: Anhydride Thermoset Reaction Study

Abstract

The development of epoxy thermosets from renewable resources is of paramount importance in a sustainable development context. In this paper, a novel bio-based epoxy monomer derived from limonene was synthesized without epichlorohydrine and characterized. In fact, this paper depicts the synthesis of bis-limonene oxide (bis-LO). However, intern epoxy rings generally exhibit a poor reactivity and allow reaction with anhydride. Therefore, we used a reaction model with hexahydro-4-methylphthalic anhydride to compare reactivity of terminal and interepoxy functions. We also studied the influence of methyl group on intern epoxy functions. Furthermore, the influence of epoxy:anhydride stoichiometry and initiator amount was studied. These studies allow to propose an optimized formulation of bis-LO. Finally, a bis-LO-based thermoset was obtained and characterized.

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

“…Thus, in the view of decreasing the environmental impact, saving petroleum resources and replacing toxic BPA for the synthesis of epoxy, bio-based thermosets are widely studied. During the last decades many research works have therefore been dedicated to the specific domain of bio-based epoxy thermosets pointing out the potential of rosin, 4 cardanol, 5 iso-eugenol, 6,7 eugenol, [8][9][10][11][12] , vegetable oil, 13 modified lignin, [14][15][16] vanillin, [17][18][19] terpene derivatives, 20 daidzein, 21 ... to replace DGEBA epoxy monomer. Among the most promising feedstocks to replace BPA, building blocks derived from lignin, have been particularly pointed out.…”

“…In parallel, different studies also underlined the importance of substituting conventional toxic polyamine hardeners by anhydrides curing agents, potentially bio-based and containing rigid ring leading to a reinforcement of the thermosets mechanical properties. 6,19,20,31,32 However, epoxy polymers are known to be highly flammable and to release a large amount of toxic smoke during their combustion. 33 Thus, different approaches more mindful of health and of the environment were recently studied to improve the flame retardancy of epoxy thermosets in order to fulfill the flammability requirements for epoxy thermosets applications.…”

Epoxy-Anhydride Vitrimers from Aminoglycidyl Resins with High Glass Transition Temperature and Efficient Stress Relaxation

“…In the base catalysed ring-opening reaction, the tertiary amine groups open the epoxy rings under the formation of alkoxides ( Figure 2 b) [ 32 , 34 , 36 ]. The alkoxides react with anhydride groups yielding carboxylate anions, which are again able to open epoxy moieties.…”

Thermosetting polymers from renewable sources

“…The reaction of polyfunctional thiols with limonene has resulted in unsaturated macromonomers that subsequently underwent free radical polymerization to yield bio‐based thermosets with properties compatible with adhesives and coatings 123 . More recently, epoxidation of limonene resulted in limonene oxide, which was converted into bis‐limonene oxide via a thiol‐ene reaction and then used in the preparation of bio‐based epoxy‐anhydride thermosetting resins 124 …”