Polymer dreams

Distiller’s grains, waste pulp, crop residues — they are the stuff of dreams for Roger Ruan, a University of Minnesota scientist.

Ruan is testing a chemical process that liquefies ag fibers for use in plastics, packaging films, foams, building materials, adhesives and a host of other manufactured goods. The research could lead to dozens of new commercial uses for ag fibers, giving farmers more markets for crop wastes; manufacturers get biodegradable, renewable raw materials.

“We know that some day our supplies of petroleum are going to run out,” says Ruan, 39, a biosystems and agricultural engineer who leads a team of scientists and graduate students at the

U of M’s St. Paul campus. “Our focus is renewable products as substitutes for petroleum. We’re trying to develop all kinds of processes to convert ag materials to useful consumer products.”

A few years ago, AURI helped Ruan’s team develop a method for high-pressure expansion of ultra-fine crop fibers. The process alters the physical properties of cellulose fibers such as sunflower hulls and corn stalks. The expanded fibers are useful in filters, time-release medicines, food additives, fertilizers and other products. AURI holds a joint patent on the process, which has been licensed to a Minnesota food company.

Ruan’s latest research uses a chemical process to break cellulose and other molecules into a liquid. The molecules are then recombined to make biodegradable polymers, which can replace petroleum-derived polymers in manufacturing.

Ruan, formerly a Pillsbury researcher, is one of the first scientists to try this total liquefaction process on crop wastes, according to Keith Sannes, a polymer chemist and AURI deputy director in Crookston. Ruan is experimenting on a variety of plant fibers, including corn cobs, beet pulp, corn stover and distiller’s grains.

These low-value materials are not economical to transport long distances. However, liquifying ag fibers for biopolymer production is fairly simple and could be done right on the farm or in the food processing plant, Ruan says. He envisions bulk trucks making the rounds to farms, much like milk trucks today, collecting polymer fluid.

The process is environmentally friendly, too, he says. “There are no emissions, no odor, no wastewater — no waste at all. It’s complete utilization.”

Ruan’s research is attracting a lot of interest, especially from the ethanol industry, which is looking for new uses for distiller’s grains, says Jack Johnson, head of AURI’s coproducts lab in Waseca. The distiller’s grain supply is expected to soar in the coming decade, depressing already low prices for the feed. Yet this surplus of cheap raw materials “could make biorefining more economical,” speeding commercialization of plant-based polymers, Johnson says.

Ruan says the research will contribute to a new era in manufacturing. “We’re at the very beginning of the biorefining industry. Within 10 years, we’ll see major advances. This industry is going to be huge.”

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