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Biological engineering graduate student Rui Xing is one of a team of students working with Chemical Engineering Professor Galen Suppes and Biological Engineering Professor Fu-Hung Hsieh to develop a soy-based foam, a sample of which sits on the table.

Efforts to identify greener, more cost-efficient materials to make the polyurethanes used to create foams and plastics has resulted in an expanded use of soybeans and soybean oils. The United Soybean Board (USB) has jumped on the bandwagon, funding research projects across the country that develop the industrial use of soybeans. In particular, they have supported projects that look to reduce dependence on petroleum-based products.

Researchers at the University of Missouri College of Engineering are recipients of a continuing grant from the USB that aims to produce a soybean oil-based foam that is not only cost-efficient to producers, but also to users. This soy-based foam is a low density, rigid material that principal investigator Galen Suppes, a professor of chemical engineering, said is in its pilot development stages. Suppes has collaborated with Fu-Hung Hsieh, an MU professor of biological engineering, for the last seven years through the various phases of the project.

Chemical Engineering J.C. Dowell Professor Galen Suppes and his research specialist, Ali Tekeei.

“Dr. Hsieh and myself have a unique set of backgrounds and capabilities to do what we do on urethane foams. Not many places have the tools and capabilities for this type of research,” Suppes said.

Soy-based polyurethane foams are made from a polyol derived from soybean oil. These foams are either rigid — for use as insulation and support materials — or flexible, with applications such as cushions.

Biological Engineering Professor Fu-Hung Hsieh. Suppes and Hsieh are collaborating on a project to produce soy foam.

The rigid soy foam produced in Suppes’ lab is created using a polyol developed over the last few years at MU. Ali Tekeei, the research specialist working with Suppes said regular soybean oil is epoxidized — heated to a temperature range that distills the moisture out — and later put through another process called polymerization that results in polyol. The product is then combined with other polyols and chemicals to make material that rises to form blocks of rigid foam. This whole process, Tekeei said, takes up to three days.

Once foam samples are made in the lab, they are measured for height, density and reaction temperature. The samples are then taken to Hsieh for further characterizations: thermal conductivity, compressive strength, closed cell content.

Images above show the foam as it expands and a finished, labeled product.

Opportunities for students

Eight graduate students are currently working with Tekeei in Suppes’ lab to make foam samples. Seven of the research assistants are international students taking part in MU Engineering’s Collaborative Academic Program (CAP). This program allows students to complete three years at a home institution and come to Mizzou to finish the requirements to earn a bachelor’s degree from their home institution, but still reap the benefits of studying abroad. Participants may then apply to graduate school at MU and, if admitted, work toward a master’s degree. Those in Suppes lab are all graduate students.

At right, Yu Shen Zhao mixes chemicals used to make soy foam and, left, Lulu Shen cuts the samples into blocks to conduct tests on them. Both chemical engineering graduate students work in Suppes’ lab.

Suppes’ lab assistants are using computer-based modeling to test and predict the outcome of different chemical combinations in a more time-efficient manner. Computer modeling offers multiple property projections on different formulations of soybean oil-based foam.

“In the past, this has been considered too complicated a task to tackle, but now we can make significant strides with the computer-based modeling,” Suppes said. “It takes money and time to do trial and error. If computer modeling similarly predicts what would happen in the lab, what would take us days to do in the lab will only take the model hours or minutes.”

Suppes said he also is incorporating the soy foam research into his senior capstone design course. There, students are tasked with formulating a plan for industrial production of the foam. The 13 students in that class are working in groups to propose how the soy-based foam could be made commercially.

“They will propose ideas on how the actual production would work and function and all the costs associated,” Suppes said.

Use in industry

“You will not deplete all the non-renewable materials from this process, but it’s much safer to dispose of what is used and the chemicals are more environmentally friendly,” Hsieh said.

But it’s too early to tell if the foam will be completely biodegradable.

Biological engineering graduate student, Rui Xing, and Harold Huff, a senior research assistant n Hsieh’s lab, conduct a compression test on a foam sample.

“It’s a mixed bag,” Suppes said about the foam’s biodegradability prospects. He said insulation foam is tricky because it’s the kind of foam you wouldn’t want to degrade while in use.

Suppes’ work with environmentally friendly technologies extends beyond the soy-based foam project. Work on a “convection battery” aims to create a more cost-efficient and quick to charge battery that would power electric vehicles. This battery includes a pump that would increase its power output to nearly six times what an identical, traditional battery would without a pump, and it performed tremendously after a series of uses and charges.

In 2006, Suppes was the academic winner of the Presidential Green Chemistry Challenge Award from the Environmental Protection Agency for his work in developing environmentally friendly antifreeze. Suppes created an efficient process for converting natural glycerin into a chemical called propylene glycol, which can be used to make antifreeze.

Some soy-based polyurethanes are already finding their way into consumer applications. Ford Motor Co. uses a soy-based flexible foam in the car seats and headrests for more than 5 million vehicles. Goodyear is researching the possibility of using soy in its tires.

The soy polyol and rigid polyurethane foam MU researchers are working on could be used as insulation, particularly in refrigerators.

Other companies currently produce soy-based rigid and spray foam insulation products. What makes this foam different is the formula. Suppes said their research is focusing on creating a better quality rigid foam product that is more cost efficient to produce.

“It’s chemically different,” Suppes said. “If you take a look at the current urethanes used in industry, there are a dozen different polyols that are widely used in different applications.”

“We’re making this foam to see if we can compete by making a more rigid, lighter and higher quality foam that’s more useful in industry,” Tekeei said. “At this point, we’re getting results and putting them together. That will tell us where we need to go.”