An eco-friendly method for preparing plant materials from pine may provide an alternative to petroleum-derived substances in the production of polyurethane foams. This breakthrough could result in greener variants of foams widely used in items such as kitchen sponges, foam cushions, coatings, adhesives, packaging, and insulation. In 2022, the worldwide market for polyurethane surpassed $75 billion.
An eco-friendly method for preparing plant materials from pine may provide an alternative to petroleum-derived substances in the production of polyurethane foams.
This breakthrough could result in greener variants of foams widely used in items such as kitchen sponges, foam cushions, coatings, adhesives, packaging, and insulation. In 2022, the worldwide market for polyurethane surpassed $75 billion.
A research team from Washington State University explored an eco-conducive method to use lignin as a replacement for 20% of the fossil fuel-derived chemicals in these foams. The resulting bio-based foam proved to be as strong and flexible as conventional polyurethane foam. Their findings are detailed in the journal, ACS Sustainable Chemistry and Engineering.
“What we’ve developed is quite unique in terms of both the material produced and the method employed,” stated Xiao Zhang, the lead author and professor at the Gene and Linda Voiland School of Chemical Engineering and Bioengineering. “The lignin we extract provides a novel class of renewable building blocks for creating high-value bio-based products.”
Plastic materials sourced from petroleum are becoming an increasingly significant waste challenge. They can take hundreds of years to decompose and are often costly and hard to recycle, frequently resulting in lower-quality second-generation products. Due to the higher costs of recycling compared to producing new plastic, recycling rates for plastics have remained below 20%, according to Zhang.
“Utilizing petroleum-based plastics results in a lose-lose scenario,” he noted. “The real answer lies in substituting them with materials derived from nature.”
Lignin is the second most prevalent renewable carbon source on the planet, constituting around 30% of non-fossil fuel-based carbon. However, it is notoriously challenging to extract from plants. Typically, it is separated during the processes of papermaking and biorefining, but these methods often lead to contamination and significant changes in its chemical and physical properties, reducing its value. As a result, most lignin ends up being burned for energy or used in low-value applications, such as cement additives or animal feed binders.
In their research, the scientists employed a mild, eco-friendly solvent to extract high-grade lignin from pine. Compared to other lignin extracts, theirs was uniform with excellent thermal stability, akin to natural lignin. This consistent structure is vital for producing high-value products.
When assessed, their formulation exhibited stability and comparable mechanical properties to traditional foams.
“Our findings indicate that the lignin formulation we developed has outstanding potential for creating flexible, bio-based polyurethane foams,” Zhang said.
The interest in producing lignin-based flexible polyurethane (PU) foams has also been supported by industrial collaborators. Zhang’s team plans to partner with these collaborators to refine and enhance the production process of lignin PU foams.
This research 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.
