Preparation And Application Of AP And NC Based Nano-Composite Energetic Material

Increasing the burning rate is one of the tasks in the property modification of composite solid propellant properties.In the nano-composite energetic material composed with oxidizer and fuel,the oxidizer and fuel are compounded in the nanometer scale,which increases the contact interface between oxidizer and fuel,so the energy release rate of the nano-composite energetic material could be greatly increased.Therefore,the addition of nano-composite energetic materials into propellant is expected to increase the burning rate.Firstly,the bulk porous thermosetting nitrocellulose（NC）was prepared by sol-gel method,and the preparation process was optimized.Secondly,porous nitrocellulose particles were prepared by the combination of emulsion method and sol-gel method.Thirdly,AP and NC granular nano-composite energetic materials were prepared by means of in situ crystallization,which made AP and porous nitrocellulose particle compound in nano scale.Then,the preparation process was optimized.Finally,the application of AP and NC granular nano-composite energetic materials in composite solid propellant was investigated.The optimized preparation conditions for the bulk porous nitrocellulose were:R_T was 1.2,the concentration of nitrocellulose was 100g·L^-1,and the reaction temperature was 35℃.The volume shrinkage of the bulk optimized porous nitrocellulose sample was 58.5%,the specific surface area was 142.25 m²·g^-1,and the average pore size was 26.77 nm.Compared with the bulk porous nitrocellulose samples,the pore size distribution of the granular porous nitrocellulose samples was more concentrated,the specific surface area was larger,and the average pore size was smaller.The particle size of granular porous nitrocellulose was mainly distributed in0⁶00μm.The optimized preparation conditions for AP and NC granular nano-composite energetic materials were:the amount of AP saturated DMF solution was 21g,and the soaking time was 2 days.The AP content in the optimized AP and NC granular nano-composite energetic material samples was 22.26 wt%,the specific surface area was 4.50 m²·g^-1,and the average pore size was 21.38 nm.Compared with pure AP,the thermal decomposition temperature of AP/NC granular nano-composite energetic materials（180℃¹96℃）was lower.Both of the explosion heat and burning rate orders of AP/NC granular nano-composite energetic materials were both as follows:AP/NC-21-48>AP/NC-21-72>AP/NC-21-24>AP/NC-16-24>AP/NC-11-24.The burning rate of AP/NC granular nano-composite materials was higher than that of AP and NC mixture.Compared with pure AP,the peak temperature of AP low-temperature decomposition decreased about 8.8℃in the propellant with AP/NC granular nano-composite materials,and the peak temperature of high-temperature decomposition decreased about 108℃.Compared with the baseline propellant,the burning rate of the propellant with AP/NC granular nano-composite materials increased about 3.05%to 3.91%,the explosion heat reduced about 3.72%,and the mechanical sensitivity changed little.