# Harnessing Eugenol for Sustainability: Synthesis and Characterization of Biobased Epoxy Thermosets

## TL;DR

Researchers created eco-friendly epoxy coatings from eugenol, a natural compound, with properties like thermal stability and antibacterial activity.

## Contribution

A novel biobased epoxy thermoset using eugenol and natural/synthetic cross-linkers is developed with tailored properties.

## Key findings

- IA-cured networks showed dual reactivity and additional cross-linking at high temperatures.
- Amine-cured networks degrade via C–O cleavage in aqueous and alkaline media.
- Acid-cured systems resist oxidation but undergo ester hydrolysis under basic conditions.

## Abstract

In this study, biobased epoxy networks were developed
from a bis-eugenol
epoxy monomer (B) cured with natural carboxylic acids such as citric
acid and itaconic acid (IA) and with synthetic amine Jeffamine D230
(D). Differential scanning calorimetry revealed distinct curing behaviors
governed by the functionality and structure of the cross-linkers.
The IA-cured network showed dual reactivity through its α,β-unsaturated
double bond, leading to additional cross-linking at elevated temperatures.
Fourier transform infrared spectroscopy confirmed complete epoxy conversion
via esterification or amino-addition mechanisms, while thermogravimetric
analysis demonstrated high char yields and no solvent residues, indicating
excellent thermal stability and potential flame-retardant behavior.
Dynamic mechanical analysis revealed glass transition temperatures
of 48–56 °C and gel contents above 96%, confirming full
curing and dense cross-linked structures. Surface analyses showed
tunable hydrophilicity and improved antibacterial activity for acid-cured
systems. Degradation and XPS studies further highlighted that the
chemical nature of the cross-linker dictates stability under corrosive
environments. Amine-cured networks degrade via C–O cleavage
in aqueous and alkaline media, whereas acid-cured systems resist oxidation
but undergo ester hydrolysis under basic conditions. These findings
demonstrate that eugenol-based thermosets can serve as eco-friendly,
corrosion-resistant coatings with adjustable flexibility and high
renewable content.