Preparation Of Spherical HMX By Piercing-solidifying Method And Characterization Of Its Properties

At present,nitroamine explosives are developing towards the direction of high energy,low cost and environmental friendliness.Among them,HMX,as a kind of energetic material with excellent performance,is often used as high explosive and rocket propellant.At the same time,in order to reduce environmental pollution,the selection of environmental protection materials for HMX bonding coating conforms to the current high energy,insensitive,green development trend.Alginate as a coating material can reduce sensitivity,improve safety performance and thermal decomposition performance to a certain extent,and has the characteristics of renewable,pollution-free and degradable.In this paper,different alginate/HMX composite energetic materials were prepared by sharp-hole coagulation bath method,and their properties were tested and characterized.The research content of this paper includes the following aspects:(1)The HMX prepared with dimethyl sulphoxide as solvent and deionized water as non-solvent presents spherical particles with smooth surface and uniform particle size distribution.Compared with the raw HMX,the crystal structure of refined HMX does not change,and the apparent activation energy and critical temperature of thermal explosion decrease by 33.16 KJ/mol and 2.65 K,respectively.The impact energy and friction pressure are increased by 2 J and 28 N,respectively,with good mechanical sensitivity and improved safety performance.By changing the deionized water,sodium alginate,the adding order of HMX,adopt the method of ultrasonic assisted mechanical agitation were different samples,the uniform suspension stability of the precursor,the following steps: first the HMX particles dispersed in water,and then will be completely dissolved sodium alginate,finally under the action of ultrasonic stirring HMX evenly dispersed in the sodium alginate solution.(2)Through single factor experiment,the optimum technological conditions for preparation of alginate /HMX composite energetic materials by piercing-solidifying method are as follows: vibration frequency 110 Hz,feeding rate 38 m L/min,sodium alginate concentration 2.0%,temperature 20? and vibration amplitude 1.The alginate /HMX composite energetic materials were prepared by different subsequent treatment,and the samples were tested and characterized.The results showed that compared with the dried sample,the surface of the lyophilized sample is more tightly coated,better thermal stability,and mechanical sensitivity is reduced to a certain extent.The results show that the surface coating of calcium alginate/HMX composite energetic materials prepared by the piercing-solidifying method is closer and the mechanical sensitivity is lower.(3)Through piercing-solidifying method make the different kinds of alginate/HMX prepared by the composite material,and testing its morphology and performance analysis found that calcium alginate,alginic acid barium,alginic acid copper coated composite can contain a uniform spherical,can use cobalt coated alginate composite containing material alginate composite containing cobalt/HMX can present a kind of ball,The size is uneven and irregular,with exposed HMX particles on the surface.The thermal decomposition peak temperature of copper alginate/HMX composite energetic materials is lower than that of refined HMX,and its thermal stability is poor compared with refined HMX.The thermal decomposition peak temperature of calcium alginate/HMX,barium alginate/HMX,cobalt alginate/HMX composite energetic materials are all increased.The apparent activation energies of HMX are 20.03,17.28 and 15.28 KJ/mol higher than those of HMX.The impact sensitivity and friction sensitivity of four different kinds of alginate/HMX composite energetic materials are finer than HMX,and the mechanical sensitivity of barium alginate/HMX composite energetic materials is the lowest.(4)The composite energetic materials with different contents of barium alginate were prepared by piercing-solidifying method and properties characterization.When the content of barium alginate was 7%,8% and 9%,a small amount of HMX particles and a large number of HMX particles were observed on the surface.When the content of barium alginate is 10% and11%,the surface is closely coated.When the content of barium alginate is 8%?10%,the thermal stability of barium alginate /HMX composite energetic material is more stable than that of refined HMX.When the content of barium alginate is 8%?11%,the impact energy of composite energetic materials is higher than that of refined HMX.With the increase of barium alginate content,the impact energy of barium alginate/HMX composite energetic material increases gradually,and its safety performance improves gradually.