Organically Modified Sol-Gel Nanocomposite for Lightweight Optically Clear Armor Protection

To address the U.S. Army need for an innovative, lightweight, optically clear polymer as armor protection for ground personnel vehicles, Physical Optics Corporation (POC) proposes to develop a new low-cost Organically Modified Sol-gel (ORMSOL) nanocomposite material to replace heavy bulletproof glass in transparent ballistic window structures. ORMSOL has excellent optical properties, thermal stability, durability, and flexibility, as well as excellent ballistic performance at a substantially reduced weight compared to current glass/polycarbonate laminates. ORMSOL is a highly crosslink-oriented nanocomposite of tetraethoxysilane and a precursor of polyurethane or polystyrene that integrates the best properties of both polymer and glass leading to higher optical transmission, higher tensile strength, and higher heat deflection temperature with 15% - 50% less weight per unit of thickness than standard glass/polymer laminates. In Phase I POC developed and fabricated ORMSOL nanocomposite samples with 3 mm thick laminates and 91%+ optical transmission, thermal stability as high as 394°C, chemical resistance to strong alkali and sulfuric acid, no polarization effect, and only 1.5% haze. The samples were tested for mechanical strength. In Phase II POC will further develop and optimize the ORMSOL material matrix, and produce scaled-up laminated prototypes that will be subjected to ballistic field testing.