A sustainable, eugenol-derived epoxy resin with high biobased content, modulus, hardness and low flammability: Synthesis, curing kinetics and structure–property relationship

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 284; pp. 1080 - 1093
• Main Authors: Wan, Jintao, Gan, Bin, Li, Cheng, Molina-Aldareguia, Jon, Kalali, Ehsan Naderi, Wang, Xin, Wang, De-Yi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.01.2016
• Subjects: Biobased epoxy resin; Curing reaction kinetics; Flammability; Isoconversional analysis; Mechanical and thermal properties; Biobased epoxy resin; Curing reaction kinetics; Flammability; Isoconversional analysis; Mechanical and thermal properties
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2015.09.031

[Display omitted] •We report a novel eugenol-based epoxy (DEU-EP).•We compare DEU-EP and DGEBA using a typical aromatic diamine (DDM) curing agent.•We model the curing rate and reveal mechanisms of DEU-EP/DDM.•DEU-EP/DDM shows enhanced modulus, hardness, char yield and reduced flammability.•Structure–property relationship of DEU-EP/DDM is established. To develop functional sustainable epoxy resins, we report a novel epoxy resin (DEU-EP) with high net biobased content (70.2wt%) derived from renewable eugenol. We comparatively study DEU-EP with a commercial bisphenol A epoxy resin (DGEBA) in the presence of a diamine curing agent, 4,4′-diaminodiphenyl methane (DDM). Differential scanning calorimetry reveals that DEU-EP can be sufficiently cured by DDM at a slower rate than DGEBA. By applying an autocatalytic reaction kinetic model we adequately simulate the curing rate of DEU-EP/DDM, and reveal its detailed kinetic mechanisms from model-free isoconversional analysis. Dynamic mechanical analysis shows that DEU-EP/DDM takes the higher storage modulus up to ∼97°C than does DGEBA/DDM with the glass temperature of 114°C. Nanoindentation and thermogravimetric analyses demonstrate that compared with DGEBA/DDM, DEU-EP/DDM exhibits a 20%, 6.7% and 111% increase in Young’s modulus, hardness and char yield, respectively. Microscale combustion calorimetry data show that DEU-EP/DDM expresses 55% and 38% lower heat release rate and total heat release than does DGEBA/DDM, respectively. The horizontal burning test approves DEU-EP/DDM can self-extinguish in a short time. Our results demonstrate that the eugenol building blocks and their arrangement greatly affect the cure behaviors of DEU-EP/DDM, and contribute significantly to its enhanced mechanical properties, high-temperature charring ability and chain motions at the glassy state, as well as the reduced flammability. To summarize, DEU-EP exhibits a high promise as a new sustainable epoxy monomer for fabricating high biobased content, high rigid and low flammable epoxy materials.