Department of Forestry Green Bioproducts Science and Engineering Lab

Lignin properties vary based on biomass source ( hardwood, softwood, and annual crops), extraction method (kraft, sulfite, soda, organosolv, enzymatic hydrolysis, and ionic liquid), and also process parameters (chemicals concentration, temperature, time, washing and drying steps). That is why it is crucial to start by measuring the chemical, physical, and thermal properties of any new lignin sample to determine its suitability for product developments.

Lignin-Based Polyurethanes

Lignin is a natural polymer made of almost one-third of the dry mass of biomass. Lignin contains both aliphatic and aromatic hydroxyl groups, making it a perfect candidate to replace petroleum-based polyol in the formulation of polyurethanes. We are working toward replacing petroleum-based polyol with lignin to formulate lignin-based polyurethane adhesives, coatings, elastomers, and foams.   

Lignin-Based Phenolic Adhesives 

Lignin is a natural polyphenolic compound made of phenyl-propane units. We previously replaced 100% of petroleum-based phenol with lignin in the formulation of phenolic adhesive. We are currently collaborating with industry partners to scale up the production of lignin-based phenolic adhesive, and test it in the plywood manufacturing lines. In parallel, we are also working on entirely replacing formaldehyde with a biobased dialdehyde (glyoxal) to have a formaldehyde-free lignin-based phenolic adhesive.

Lignin-Based Epoxy 

Lignin can also be used to replace toxic bisphenol-A (BPA) in the formulation of epoxy resins. We formulated a fully biobased epoxy resin by entirely substituting bisphenol-A with lignin and using biobased epichlorohydrin and biobased curing agent. We are working on using lignin-based epoxy resin to formulae biobased epoxy coatings, adhesives, and composites.