Self-healing plastics on the way?

Researchers in Germany have created a self-healing polymer that can fully restore its mechanical properties in just a few minutes when heated at relatively low temperatures.

The material, developed by a team from the Karlsruhe Institute of Technology (KIT), could be used to create fibre-reinforced plastics for the automotive and aerospace industries, as well as scratch-resistant paints and self-repairing sealants. To begin, the researchers created a switchable network of cross-linked fibres bonded by a reversible chemical reaction. They found that these so-called switchable networks could be de-composed into their initial constituents and re-assembled again after the damage. The self-healing mechanism can be initiated any time by heat, light or by the addition of a chemical substance. What's more, the method requires no catalyst, works at relatively low temperatures (between 60 and 120°C), and exhibits excellent healing properties within a few minutes. The researchers also found that their method can be applied to a number of other known plastics. Mechanical tests, such as tensile and viscosity tests, confirmed that the original properties of the materials can be restored completely. "We succeeded in demonstrating that test specimens after first healing were bound even more strongly than before," said group leader Professor Barner-Kowollik.