Experimental and Modeling Characterization of PETN Mobilization Mechanisms During Recrystallization at Ambient Conditions

Burnham, A K ; Gee, R ; Maiti, A ; Qiu, R ; Rajasekar, P ; Weeks, B ; Zepeda-Ruiz, L

Lawrence Livermore National Laboratory

关键词: Lawrence Livermore National Laboratory;    Evaporation;    Thermal Cycling;    37 Inorganic, Organic, Physical And Analytical Chemistry;    Kinetics;   

DOI  :  10.2172/886924
RP-ID  :  UCRL-TR-216963
RP-ID  :  W-7405-ENG-48
RP-ID  :  886924

美国|英语

来源: UNT Digital Library

【 摘 要 】

Experimental measurements suggest that pentaerythritoltetranitrate (PETN) undergoes changes at the molecular level that cause macroscopic changes in the overall PETN powder characteristics over time. These changes have been attributed to the high molecular mobility of PETN, but the underlying mechanism(s) responsible for this redistribution are still uncertain. Two basic approaches have been implemented in the past year to provide insight into the nature of these underlying mechanisms. The first approach is of an experimental nature, utilizing both AFM and evaporation measurements, which address both surface mobility and evaporation. These data include AFM measurements performed at LLNL and evaporation rate measurements performed at Texas Tech. These results are compared to earlier vapor pressure measurements performed at SNL, and estimates of recrystallization time frames are given. The second approach utilizes first-principle calculations and simulations that will be used to compare directly to those experimental quantities measured. We are developing an accurate intermolecular potential for PETN, which via kinetic Monte Carlo (KMC) simulations would mimic real crystallite shapes. Once the basic theory is in place for the growth of single crystallites, we will be in a position to investigate realistic grain coarsening phenomena in multi-crystallite simulations. This will also enable us to study how to control the morphological evolution, e.g., through thermal cycling, or through the action of custom additives and impurities.