ALTERING THE IMPACT-DRIVEN SENSITIVITY AND IGNITION OF PVDF-TrFE/nAL COMPOSITES

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ALTERING THE IMPACT-DRIVEN SENSITIVITY AND IGNITION OF PVDF-TrFE/nAL COMPOSITES WITH PIEZOELECTRICITY

thesis
posted on 30.07.2021, 05:19 by Derek Keith MesserDerek Keith Messer

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 (d33). 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 d33 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 d33 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.

Funding

FA9550-19-1-0008

History

Degree Type

Master of Science in Aeronautics and Astronautics

Department

Aeronautics and Astronautics

Campus location

West Lafayette

Advisor/Supervisor/Committee Chair

Dr. Steven F. Son

Additional Committee Member 2

Metin Örnek

Additional Committee Member 3

Christopher S. Goldenstein

Additional Committee Member 4

Sally P. M. Bane