A new transparent thermoplastic elastomer (TPE) armor developed by the United States Naval Research Laboratory (NRL) is far stronger than bulletproof glass and can be easily repaired once damaged.

The U.S. Navy's TPE armor is also lighter than conventional bullet-proof glass.

Thermoplastic elastomers are soft, rubbery polymers that can be converted into a solid trough physical means instead of a chemical process. The solidification is reversible, and facilitates the repair in the field of armor damaged by bullet strikes and shrapnel.

"Because of the dissipative properties of the elastomer, the damage due to a projectile strike is limited to the impact locus," said Dr. Mike Roland, NRL Soft Matter Physics senior scientist.

"This means that the effect on visibility is almost inconsequential, and multi-hit protection is achieved."

He explained that heating the TPE above the softening point of around 100 degrees Celsius melts the small crystallites, enabling the fracture surfaces to meld together and reform via diffusion.

"This can be accomplished with a hot plate, akin to an iron, that moulds the newly forming surface into a smooth, flat sheet with negligible effect on integrity."

NRL scientists have tested polymeric materials for use as a coating to obtain enhanced impact resistance of hard substrates.

They've found that the ballistic performance of armor and helmets can be improved with the application of polyurea and polyisobutylene layers, along with attaining enhanced ballistic effectiveness and mitigation of blast waves.

The TPE armor technology of NRL is covered by US Patent #9,285,191; Polymer Coatings for Enhanced and Field-Repairable Transparent Armor.

NRL is seeking licensees to manufacture its patented TPE armor.