Preparation And Properties Of GAP/F₂₆₀₂/CL-20 Composite Energetic Fiber/microsphere

Hexanitrohexaazaisowurtzitane(CL-20)is an energetic material with high energy and density.It is limited in practical applications due to its high sensitivity.In order to reduce the sensitivity of CL-20,polyglycidyl azide(GAP)and fluororubber(F₂₆₀₂)were used as binders to compound with CL-20.GAP/F₂₆₀₂/CL-20 composite energetic fiber and micronsphere were prepared through safe and simple electrospinning/electrospray technology based on electrostatic fluids.The main research contents were as follows.A polymer bonded explosive model was constructed with CL-20 as a high energy explosive and GAP/F₂₆₀₂as composite binders.The binding energy,cohesive energy density,mechanical properties and electrostatic potential between GAP/F₂₆₀₂and CL-20 were simulate and calculate by Material Studio software.The results showed that the binding energy between GAP/F₂₆₀₂and CL-20 is positive,indicating that the composite system can exist stably.The introduction of GAP/F₂₆₀₂into the system improveed the mechanical properties of CL-20 by increasing the tensile modulus and reducing rigidity of CL-20.The bond energy of N-NO₂in the CL-20 molecule was changed,thereby the sensitivity of CL-20 improved.The GAP/F₂₆₀₂/CL-20 composite materials were prepared by electrospinning and electrospray technology.The influence of solution concentration,binder content,applied voltage and injection rate on its morphology were explored.By optimizing the electrospinning/electrospray process,GAP/F₂₆₀₂/CL-20 composite energetic fibers and microspheres with average diameter of 385 nm and 660 nm were obtained.The morphology and structure,mechanical sensitivity and energy properties of GAP/F₂₆₀₂/CL-20 composite fibers and microsphere were tested and analyzed.The results showed that the surface of GAP/F₂₆₀₂/CL-20 fiber/microsphere contained four elements:C,N,O,F,and-N₃,-CF₃,-NO₂and other groups,all of which came from the sample components.It showed that GAP/F₂₆₀₂could be well combined with CL-20.There was not chemical reaction and no impurities were introduced during the process of electrospinning.Compared with the mechanical sensitivity of raw CL-20,the friction sensitivity of GAP/F₂₆₀₂/CL-20composite fiber and microsphere decreased by 48%and 20%,and the characteristic drop height(H₅₀)increased by 45.3 cm and 30.5 cm,respectively.The standard specific impulse of the fiber and the microsphere are 2668.1 N·s·kg^-1and 2675.7 N·s·kg^-1,which are comparable to raw CL-20.It indicated that the GAP/F₂₆₀₂/CL-20 composite energetic fiber/microsphere can not only maintain a high energy leve,but also effectively solve the problem of CL-20's high sensitivity.