UH Engineers Develop “Bulletproof” Coatings

Alamgir Karim, Dow Chair Professor of chemical and biomolecular engineering, says the chitin project could lead to more environmentally friendly plastics and other polymers. Photo courtesy of University of Houston – Cullen College of Engineering. A trio of engineers from the University of Houston (UH) (Houston, Texas, USA) have developed a process that uses chitin, a glucose derivative found in the cellular walls of arthropods and fungi, and 3D-printing techniques to produce high-impact multilayered coatings that can protect soldiers against bullets, lasers, toxic gas, and other dangers.

According to Alamgir Karim, Dow Chair Professor of chemical and biomolecular engineering, chitin is a promising alternative to corn as a sustainable, bio-based material in that it can be processed and used in products that require petroleum-based plastics.

“What if we could process these materials and get them to a certain level of performance, so we could do some really good things in the plastics world?” asks Karim, who also serves as director of the International Polymer & Soft Matter Center and of the materials engineering program at UH. “They would be biodegradable by design, so they could decompose and return to Mother Nature.”

Karim is principal investigator on the project, with Venkatesh Balan, assistant professor of engineering technology, and Megan Robertson, associate professor of chemical and biomolecular engineering, as co-principal investigators. The project is funded by a $660,000 grant from the U.S. Department of Defense (Washington, DC, USA).

Karim, Balan, and Robertson are charged with developing tough, durable, antimicrobial multilayer films that can resist an impact from projectiles or lasers, or that can absorb toxic gas. In addition to its military applications, the work should also have environmental benefits, says Karim.

Balan is using chemical and enzymatic processes to produce chitosan, or de-acetylated chitin, a fiber that is also produced and sold as a dietary supplement. He says that his lab is trying a similar approach with mushrooms, which yield a more consistent degree of polymerization sustainability and aids in the processing of chitin into chitosan.

Robertson’s role is to determine how to alter the atomic composition at the surface of the chitosan so that it can better interact with the functional layers. She says that the enhanced compatibility between the chitosan and the polymer will improve the coating’s ability to trap gas or absorb projectile impact.

As for Karim, he is engineering a multilayer system comprised of the following: a hardened impact-resistant layer; an energy-absorbing crush layer; a layer to absorb toxic gas; and a textile adhesion layer. This process will involve 3D printing different chitin nanoparticles and chitosan-fabricated or reinforced crush-zone design structures, along with testing them to determine if they can withstand an impact. “It is a very good, environmentally friendly project,” Karim says

Source: University of Houston – Cullen College of Engineering, www.egr.uh.edu.