A research team from Washington State University replaced 20% of the polyurethane foam's fossil fuel-based chemicals with an eco-friendly lignin preparation. Like regular polyurethane foam, the bio-based foam was equally robust and pliable. The journal ACS Sustainable Chemistry and Engineering published the study.
Ziqi Yu (Postdoc), Isaac Nartey Oduro (PhD student) and Daniela Gonzalez- Sepulveda (undergraduate RA) are examining lignin-based polyurethane samples. Image Credit: Washington State University
Pine plant material could be prepared in an environmentally friendly way to replace petroleum-based chemicals in polyurethane foams.
The invention may result in more ecologically friendly foams, which are widely used in insulation, foam cushions, coatings, adhesives, kitchen sponges, and packaging. In 2022, the polyurethane market was worth over $75 billion worldwide.
It is quite novel in terms of the material we generate and the process we have. Our extracted lignin offers a new class of renewable building blocks for the development of bio-based value-added products.
Xiao Zhang, Study Corresponding Author and Professor, School of Chemical Engineering and Bioengineering, Washington State University
Plastics made from petroleum are becoming a bigger waste issue. Although they are costly and challenging to recycle, they take centuries to decompose and typically result in a subpar second-generation product. According to Zhang, the plastics recycling rate has continuously remained below 20% because recycling is more expensive than producing new plastic.
It is basically a no-win situation if you are using petroleum-based plastics. The ultimate solution is to replace them with naturally derived materials.
Xiao Zhang, Study Corresponding Author and Professor, School of Chemical Engineering and Bioengineering, Washington State University
About 30% of the carbon on Earth that is not derived from fossil fuels comes from lignin, making it the second most abundant renewable carbon source. Additionally, it is infamously hard to extract from plants.
Papermaking and biorefining typically separate the material, but these processes frequently contaminate it and drastically change its chemical and physical properties, lowering its value. Therefore, most lignin is either burned to create electricity and fuel or used to make low-value products like animal feed binders or cement additives.
In their study, the researchers separated high-quality lignin from pine using a gentle, eco-friendly solvent. Their formulation was similar to native lignin in terms of homogeneity and good thermal stability when compared to other lignin formulations. The ability to create high-value products depends on structural homogeneity.
Their product was stable and mechanically performed on par with the traditional foams when they tested their formulation.
This work demonstrates that our prepared lignin formulation has a great potential for generating flexible, bio-based polyurethane foams.
Xiao Zhang, Study Corresponding Author and Professor, School of Chemical Engineering and Bioengineering, Washington State University
Industry partners also confirmed interest in creating flexible lignin-based polyurethane (PU) foam. Zhang's team will now optimize and scale up the production of lignin PU foam in collaboration with the industrial partners.
The study was supported by the National Science Foundation’s Industry-University Cooperative Research Center for Bioplastics and Biocomposites (CB2), the USDA National Institute of Food and Agriculture programs, and WSU’s Office of Commercialization.
Journal Reference:
Wang, C., et al. (2025) Deep Eutectic Solvent-Extracted Lignin for Flexible Polyurethane Foam Preparation. ACS Sustainable Chemistry & Engineering. doi.org/10.1021/acssuschemeng.4c08370.