Propulsion and Energetics/Energetic Materials: Optical Characterization of Subsurface Reactions in Heterogeneous Materials

Abstract

Explosives and propellants are heterogeneous materials consisting of energetic molecular crystals embedded in polymeric binders. Additional components may include plasticizers, antioxidants, taggants/markers, friction-generating grit, etc. These energetic materials can be initiated through a variety of stimuli, including thermal, mechanical, and electrical means, with the non-thermal stimuli believed to generate heat first which then causes thermally induced chemical decomposition. Optimizing the performance of energetic materials for specific applications must be balanced against safety and reliability considerations. This process requires an improved fundamental understanding of the chemical reactions inside the material. The proposed research effort focuses on developing an experimental microscopy approach for probing sub-surface sample volumes in scattering condensed phases via Raman and Laser-Induced Fluorescence (LIF) spectroscopy. Our approach uses a phase-modulation technique combined with isotropic focusing and bidirectional optical phase correction to compensate for scattering in the sample. A successful completion of this proposed research effort would provide the experimental capability to measure sub-surface Raman and LIF spectra in heterogeneous materials. The ability to make such measurements would be the first step toward monitoring in real-time sub-surface chemical reactions in scattering heterogeneous materials such as energetic materials. Subsequent efforts would focus on implementing faster compensation techniques to monitor dynamically changing conditions, such as encountered in chemical reactions, inside heterogeneous materials.

Document Details

Document Type
DoD Grant Award
Publication Date
Sep 11, 2018
Source ID
W911NF1810094

Entities

People

  • Hergen Eilers

Organizations

  • Army Contracting Command
  • United States Army
  • Washington State University

Tags

Fields of Study

  • Physics

Readers

  • Nanocomposite Materials Science
  • Optical Physics and Photonics.
  • Rocket Propulsion.

Technology Areas

  • Directed Energy