Synthesis and characterization of hydrolysis lignin-based epoxy resins

• Bio-based epoxy resin was produced from de-polymerized hydrolysis lignin (DHL).
• Curing kinetics of bio-based epoxy resin were studied using non-isothermal DSC.
• Bio-epoxy resins had higher carbon residue compared to a common epoxy resin.
• Composites comprising up to 50 wt% of DHL-epoxy showed great mechanical properties.

A novel bio-based epoxy resin was synthesized using de-polymerized hydrolysis lignin (DHL) as a feedstock under alkaline condition. The chemical functionality of DHL-based epoxy resin was studied using Fourier Transformation Infrared spectroscopy (FTIR).The curing behavior of DHL-based epoxy resin with a selective curing agent (4,4′-diaminodiphenyl methane; DDM) was also investigated using differential scanning calorimetry (DSC). The curing process was found to proceed via a ring opening reaction involving the epoxy and the amine groups followed by etherification reactions at the end. The thermal and mechanical behavior of the resulting DHL-based epoxy resin were investigated using a thermogravimetric analysis (TGA) and a universal testing machine (UTM), respectively. The cured DHL-based epoxy-DDM system demonstrated good thermal and mechanical performances, suggesting its potential of utilizing hydrolysis lignin—a byproduct/waste stream from cellulosic ethanol processes for the production of value-added bio-based materials.