<p>Throughout the last century,
energetic materials have been subject to drop weight impact tests to measure
their sensitivity, with which material’s properties are correlated to their
impact sensitivity. However, there is little research that focuses on utilizing
the piezoelectric effect to control the sensitivity of energetics.
Piezoelectricity is the effect of an electric charge accumulating due to an
applied mechanical stress. It is demonstrated in previous work that
fluoropolymers such as polyvinylidene fluoride (PVDF) contribute to higher
sensitivity in nanocomposite energetic materials through their piezoelectric
properties. This property can be amplified in fluoropolymers in the beta (β) phase
through polling methods and can be quantitatively analyzed by the piezoelectric
coefficient (d<sub>33</sub>). This research is focused on characterizing the
effect of piezoelectricity on the impact sensitivity and ignition delay of nAl/PVDF-TrFE
composites through the presence of varied d<sub>33</sub> coefficients. The
composite films were fabricated with the tape casting method with 85 μm
thickness. The content of nAl was limited to 10 wt% in order to sustain
feasible poling. Poling was achieved without any further manipulation of the
composition so that a direct comparison could be observed. The magnitude of
effect that the piezoelectric coefficient has on an energetic composite was
discovered. The samples that had no d<sub>33</sub>
value were 8% less sensitive and experienced longer ignition delay times
compared to the poled samples. This work proved that impact sensitivity and ignition delay
can be manipulated through poling methods. This concept of controlling the
sensitivity of energetic materials can be used to develop more customizable
composites in the future.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/15078801 |
| Date | 29 July 2021 |
| Creators | Derek Keith Messer (11205612) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/ALTERING_THE_IMPACT-DRIVEN_SENSITIVITY_AND_IGNITION_OF_PVDF-TrFE_nAL_COMPOSITES_WITH_PIEZOELECTRICITY/15078801 |
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