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Title: Impact Sensitivity and Ignition Mechanisms of Nanoaluminum-poly(perfluorinated methacrylate) Nanocomposites

Journal Article · · MRS Advances
DOI:https://doi.org/10.1557/adv.2018.339· OSTI ID:1482925
 [1];  [2];  [2];  [3];  [4];  [4];  [1]
  1. United States Army Armament Research, Development and Engineering Center (ARDEC), Picatinny Arsenal, NJ (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Purdue Univ., West Lafayette, IN (United States). School of Aeronautics and Astronautics
  4. Purdue Univ., West Lafayette, IN (United States). School of Mechanical Engineering
+ Show Author Affiliations

Nanoenergetic composites are of overwhelming interest to the Department of Defense because of the higher power output and the ability to finely tune the ignition thresholds of these composites. Recently, several variants of a nanoaluminum-poly(perfluorinated methacrylate) (AlFA) have been synthesized and optimized for a variety of applications including reactive warhead liners and bullet spotters. While conventional techniques such as thermal analysis and bomb calorimetry can be used to characterize the reaction mechanism and energy output of AlFA composites, characterizing their dynamic behaviour is more challenging. Bullet spotter applications require a material to be impact sensitive at very low velocities, yet be adequately insensitive. Several live-fire tests were conducted which revealed the AlFA50 material reacted consistently upon target impact at high velocities, but unreliably at very low velocities. In an effort to better understand the fundamental impact ignition mechanism and to determine the impact velocity threshold of AlFA50 a series of Taylor gas gun experiments were conducted. It was determined that the light-initiation mechanism was consistent with a pinch mechanism, and that the ignition velocity threshold was near 74 m/s. Based on these results, it was hypothesized that the addition of a filler material could be used to sensitize the AlFA50, and that Asay shear impact testing could be used to determine a more optimal shape of such inclusions. Experiments performed using the Asay shear impact test setup confirmed the pinch ignition mechanism, but observations also revealed that the size of the pinch point was important. It was shown that the addition of large glass beads (> 1mm in diameter) was effective at sensitizing the AlFA50 material at high and low velocities, with ignition observed at impact velocities as low as 35 m/s.

Research Organization:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); United States Army Armament Research, Development and Engineering Center (ARDEC), Picatinny Arsenal, NJ (United States)
Sponsoring Organization:
USDOE; USDOD
Grant/Contract Number:
89233218CNA000001
OSTI ID:
1482925
Report Number(s):
LA-UR-18-21291
Journal Information:
MRS Advances, Vol. 3, Issue 17; ISSN 2059-8521
Publisher:
Materials Research Society (MRS)Copyright Statement
Country of Publication:
United States
Language:
English

References (8)

The transition from burning to detonation in cast explosives journal March 1965
Impact Initiation of Reactive Aluminized Fluorinated Acrylic Nanocomposites journal April 2016
Impact-induced friction ignition of an explosive: Infrared observations and modeling journal October 2010
Combustion of damaged PBX 9501 explosive journal February 2002
Synthesis and reactivity of aluminized fluorinated acrylic (AlFA) nanocomposites journal October 2012
Thermodynamic Modeling of Pyrotechnic Smoke Compositions journal March 2016
Quantification of reaction violence and combustion enthalpy of plastic bonded explosive 9501 under strong confinement journal January 2005
Interplay of explosive thermal reaction dynamics and structural confinement journal April 2007

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36 MATERIALS SCIENCE
nanoscale
energetic material
polymer