Al@GAP复合粒子对LLM-105热分解性能的影响

为防止铝粉在存储中氧化失活,同时为含铝炸药配方设计提供借鉴,采用聚叠氮缩水甘油醚(GAP)对不同尺寸Al粉(平均粒径分别为50nm和1~2μm)进行包覆改性,获得Al@GAP复合粒子;采用扫描电镜(SEM)、透射电镜(TEM)表征其形貌;用差示扫描量热法(DSC)对不同质量比的(Al@GAP)/LLM-105混合体系的热分解过程进行了研究。结果表明,采用两步包覆法获得了不同尺寸Al粉表面包覆GAP的核壳结构复合粒子;相较于包覆前的微米级Al粉,加入GAP包覆的纳米Al粉后混合体系的热分解峰温明显降低;当Al粉质量分数大于10%时,GAP包覆后的(Al@GAP)/LLM-105混合体系的熵变(ΔS~≠)和焓变(ΔH~≠)较Al/LLM-105混合体系有所减小;(Al@GAP)/LLM-105混合体系的活化能、热爆炸临界温度及热力学参数ΔS~≠和ΔH~≠随纳米Al粉含量的增加而降低,当Al粉质量分数为30%时,较LLM-105分别降低4kJ/mol、3℃、4.3J/(mol·K)、4.2kJ/mol。

Effect of Al@GAP Composite Particles on Thermal Decomposition Performance of LLM-105

To prevent the oxidative inactivation of aluminum powders during storage, and provide references for formulation design of aluminized explosives, aluminum powders with different size were coated and modified using glycidyl azide polymer (GAP) to obtain Al@GAP composite particles.The surface morphologies of the composite particles were characterized by scanning electron microscope (SEM) and transmission election microscope (TEM).The thermal decomposition processes of (Al@GAP)/LLM-105 mixture with different mass ratio were investigated by differential scanning calorimetry (DSC).The results show that the composite particles with core-shell structure of different size of aluminum powders coated with GAP are obtained through two-step coating method.Compared with micro-Al powder before coating, the decomposition temperature of Al nanoparticles coated by GAP is obviously reduced.When the mass fraction of Al powder is more than 10%, the entropy change (ΔS≠) and enthalpy change (ΔH≠) for the mixed system of adding GAP were lower than those of Al/LLM-105.The activation energy,critical temperature of thermal explosion and the thermodynamic parameters ΔS≠ and ΔH≠ of (Al@GAP)/LLM-105 mixed system decrease with increasing the content of Al nanoparticles, when the mass fraction of Al powder is 30%, they reduced by 4kJ/mol, 3℃, 4.3J/(mol·K) and 4.2kJ/mol compared with LLM-105, respectively.