Recently, US scientists discovered that a commercially sold polymer - used to coat bowling pins, helmets and golf balls, displays a curious property when shot at: it can immediately "pave over" the bullet holes. "Surlyn" the well-known ethylene-acrylic copolymers, generally used in packaging applications or for providing dispersion of pigments in masterbatches, is found to have a new application. Traditionally Surlyn makes golf balls tough. In it's new found application, Surlyn helps a product heal under bullet shots instead of fracturing. A sheet of Surlyn when shot by bullets, has found to self heal without breaking.

A team of materials engineer at the US Naval Air Systems Command is trying to understand why the polymer self-heals. Apparently melting properties of the material may explain why it self-heals. The speeding bullets heat the Surlyn to temperatures close to its melting temperature. The melting properties appear to depend on Surlyn's polyethylene chains and methacrylic acids. These comprise a random mixture of ionic and nonionic regions that each want to stay with their kind. The polymer however disintegrates when it touches fuel. The other navy research teams are working on ways to bond it with a fuel-resistant material such as urethane, which could bring it to the market relatively quickly.

Once the solution is found, Surlyn or its variant could play a very important role in the construction of fighter aircraft.