The search for more sustainable and less toxic polymer composite materials is leading many researchers to use plant-derived renewable resources to develop a number of technologies with properties and performances similar to petroleum-derived composites, according to Dr. John J. La Scala, Associate for Science & Technology for Weapons and Materials Research Directorate of the Army Research Laboratory in Aberdeen Proving Ground, Maryland.

La Scala recently visited the Georgia Tech campus at the invitation of Meisha Shofner, associate director of the Renewable Bioproducts Institute and associate professor, MSE. His work ties in particularly well to one of the focus areas of RBI — lignin-derived chemicals.

"Efforts to utilize lignin in applications such as carbon fiber production could lead to greater utilization of composite materials in a host of structures, exceeding those accommodated by the current market size,” Shofner said. “Similarly motivated research at RBI and GT is seeking to fill this need in the carbon fiber market."

La Scala’s research has formulated and developed fatty acid-based vinyl ester resins derived from plant oils and successfully demonstrated and validated them on weapons platforms across the DoD.  The chemically modified lignin is used to produce lignin-based carbon fiber with the highest reported strength and modulus. 

He has also been working on ways to address the toxicity issues associated with bisphenol, a component used in the production of many high performance polymers.  Through use of polymers from lignin-derived chemicals, such as guaiacol, and carbohydrate-derived isosorbide and furans, his team has created a number of polymers with properties similar or superior to that of commercial polymers.  They’ve also shown that these bio-based chemicals and polymers have reduced toxicity relative to the baseline commercial polymers. 

As a result, La Scala said, they are preparing diamines derived from carbohydrates and lignin to reduce the toxicity and improve the sustainability of polyimides and epoxies.

"Replacing or reducing utilization of petroleum-derived chemicals in the production of polymer-based materials and composites is an important goal,” Shofner said. “Though current petroleum pricing reduces some of the motivation to seek bio-based alternatives, these solutions will have to be developed in the future to address supply concerns. Dr. La Scala's work has addressed this need on multiple fronts while seeking to balance performance issues, leading to solutions that can be potentially implemented in the near term."

Dr. John La Scalais a scientist at the Army Research Laboratory (ARL) and was recently appointed as the Weapons and Materials Research Directorate Associate for Science & Technology.  Throughout his career, he has continued his work in bio-based thermosetting resins, where he now has 18 years of experience.  Since joining ARL, he has expanded his work to thermosetting resins for adhesives and coatings and environmentally friendly polymers for composites, adhesives, coatings, and engineering applications.