New biopolymer gives asphalt roads a soybean-based-boost

Along with their use in foods, soybeans have also been utilized as a source of graphene, a greener alternative to mulch, and an ingredient in longer-lasting tires. Now, they're additionally being used to extend the life of asphalt roads.

Usually, in order to make asphalt more pliable and thus less likely to crack, a synthetic rubber known as polybutadiene is added to it. Not only is that rubber in short supply, but it's also carcinogenic – and as is the case with other petroleum-based materials, the process by which its raw ingredients are obtained isn't very eco-friendly.

With these drawbacks in mind, scientists at Iowa State University looked to soybeans as an alternative. Led by Prof. Eric Cochran and Dr. Christopher Williams, they eventually developed a process for converting soybean oil into a biopolymer that closely matches the performance of polybutadiene.

The production process was initially a bit impractical, as it required the oil to pass through three reactors over a 24-hour period. Now, in a process called Poly100, batches of the biopolymer can be produced in just a few hours via a single reactor. According to the university, no volatile organic compounds are produced, and none of the oil is wasted.

The technology has been commercialized by spinoff company SoyLei Innovations, which is marketing the biopolymer under the trade name of BioMAG. It's being offered in several variants, including one for use in virgin asphalt, one that allows a greater amount of recycled asphalt to be used in roads, and one that helps rejuvenate asphalt shingles.

It should be noted that while the farming of soybeans may seem eco-friendly as compared to the mining of oil required for petroleum-based materials, there are still some concerns regarding its effects on the environment. For instance, the majority of soybeans are grown in Brazil, where large areas of rainforest are cut down in order to make way for farms. Additionally, shipping the beans from Brazil to other markets contributes to greenhouse gas emissions.

Sources: Iowa State University, SoyLei Innovations