Laser shock loading of carbon nanotube and ceria polyurea composites

Abstract

A series of Versalink® P1000 and Mondur CD (polymers of approximately 1000 amu) polyurea samples were loaded with ceria (CeO2) nanoparticles and carbon nanotubes (CNTs), shocked using direct laser impulse testing, and their response was measured by photonic Doppler velocimetry. A novel method for a near universally applicable ablation layer was employed by depositing titanium onto one side of the polyurea nanocomposite disk, followed by a reflective layer of aluminum on the reverse side via sputter deposition. Relative to the 73.6% baseline attenuation of pure P1000 polyurea, nanoparticle addition increased incident-pressure attenuation to up to 88.3%. The ceria nanocomposites exhibited a decreased Hugoniot elastic limit, indicating increased quantities of micropores and microfracture sites to facilitate shock hysteresis. In contrast, CNT nanocomposites displayed an increased initial shock without a visible plastic deformation peak, followed by a slower secondary hysteresis wave as CNT loading increased. These findings can guide the development of composite dampeners for synthetic armors and similar applications.