This week in adhesives news, a new polymer damage indication system will flag automatically cracked, scratched, or stressed areas to allowing engineers to address the material or structural problem.
The research was led by Nancy Sottos, professor of materials science and engineering at University of Illinois, and Scott White, aerospace engineering professor.
“Polymers are susceptible to damage in the form of small cracks that are often difficult to detect,” said Sottos. “Even at small scales, crack damage can significantly compromise the integrity and functionality of polymer materials. We developed a very simple but elegant material to autonomously indicate mechanical damage.”
Microcapsules of a pH-sensitive dye work in an epoxy resin, breaking open if the polymer forms cracks or suffers a scratch, stress or fracture. The dye reacts with the epoxy, causing a color change from light yellow to a bright red. The deeper the scratch or crack, the more microcapsules are broken, and the more intense the color. Differences in the intensity of the color can help to determine the extent of the damage. Cracks as small as 10 micrometers are enough to cause a color change, letting engineers know that the material has lost some of its structural integrity. An early warning system could be useful in petroleum pipelines, air and space transport, and automobile applications, where the failure of one part could have a ripple effect on other parts and create costly problems that are difficult to repair.
Other stories from around the web: