Iowa State University researchers are developing biorenewable polymers capable of healing themselves as they degrade and crack.

Lead researcher Michael Kessler said that the results of this research might provide biorenewable alternatives to petroleum-based resins.

The technology has evolved into a system that embeds catalysts and microcapsules containing a liquid healing agent within a composite. As cracks develop in the composite, they rupture the microcapsules and release the healing agent.

The healing agent contacts the catalyst and reacts by forming 3-D polymer chains that fill the cracks. That increases material lifetimes and reduces maintenance.

Kessler's research has found that a healing agent for a polymer based on tung oil works too fast. Kessler and Peter Hondred, an Iowa State graduate student in materials science and engineering, are working to slow the agent for better healing.

The researchers are also working to develop encapsulating techniques that work with biorenewable polymers. And they're working to develop bio-based healing agents.

Despite the challenges, Kessler said that there is potential to develop self-healing, biorenewable materials.

However, the big question is whether researchers can push the healing efficiency of biorenewable polymers close to the 90 percent of standard composites, he added.