We used a new formulation of lignin-polyol with higher lignin content (from 1:10 to 1:5 ratio of lignin to green solvent), then prepared foams using a mixture of soy-polyol (20%) and lignin-polyol (20%) to replace 40% of petroleum-based polyol in the formulation polyurethane (PU) flexible foams. We successfully formulated PU flexible foam with 30% biobased carbon content for automotive seating, which is the largest piece of foam in cars and the most challenging one. Foam samples were analyzed by measuring their densities, tensile strengths, ultimate elongations, tear strengths, compression force deflections, support factors, and compression sets. The developed soy-lignin-based foams (LP20/SP20) met all the standard requirements for automotive seating except elongation at the break, which we believe can be adjusted by increasing the amount of soy-polyol in the foam from 20% to 30% due to the flexible nature of soy-polyol, we will continue our formulation optimization to meet all the standard criteria for seating. For the biodegradation test, the polyols and foams were evaluated in compost under controlled conditions at 37°C and 58°C by analysis of evolved CO2 using an in-house built direct measurement respirometer (DMR). According to the percentage mineralization, the soy polyol reached mineralization values higher than 100% by 180 days at 37°C due to priming. At the same time, lignin polyol reached mineralization values of 66%. The developed foams with higher biobased carbon content (increased from 22% to 30% this year) achieved 29% mineralization (biodegradation) within 120 days at 58°C thermophilic composting condition. For the chemical recycling method, the glycolysis approach was selected for recycling biobased foams. The ATR-IR and NMR results indicate that recycled polyol can be obtained from glycolysis products that have the potential to be used for recycled flexible and rigid polyurethane. The previous project focused on biobased foams for insulation panels and under-carpet flooring. However, this year, we both increased the biobased carbon content of our foams and targeted automotive seating applications.

Prior to this project, the maximum amount of soy-polyol used in PU car parts was around 8-10%. So far, we have shown that we can have a working foam that contains 20% soy-polyol and 20% lignin-polyol for automotive seating applications. With USB-approved funding for another year, we plan to increase the biobased content of the foams further. The results of this work will help Ford and other automotive producers reach their sustainability goals while creating an exceptionally high-end larger market for soy produced in the US. The successful implementation of this unique project will open a market of ~512,000 tons/year for lignin and soy-based polyols.