溶液参数对n-Al/F2604复合粒子微观形貌的影响机制

Influence Mechanism of Solution Parameters on the Micro-morphology Structure of Nano-Aluminum/F2604 Composite Particles

为了揭示氟橡胶对纳米铝粉的包覆机理,以静电喷雾技术,利用不同溶剂(乙酸乙酯和丙酮)制备了不同氟橡胶(F2604)含量的复合粒子,用扫描电子显微镜(SEM)表征了复合粒子的形貌,采用实验与分子动力学模拟相结合的方法研究了溶液参数对n-Al/F2604复合粒子微观形貌的影响。结果表明,丙酮作为溶剂可使得复合粒子形貌更为均匀规整,氟橡胶含量小于13%时,复合粒子直径随着氟橡胶比例增加而增大;当氟橡胶含量继续增加,复合粒子粒度分布变得不均,形状不规则,出现明显的纺丝现象。氟橡胶在溶剂中的扩散系数是影响其包覆纳米铝粉时分子链形态的重要因素之一,因此,在选择溶剂时应当遵循"氟橡胶扩散系数大"原则;氟橡胶与纳米铝粉的单位结合能主要由静电力作用能(75%～93%)和范德华作用能(6%～22%)组成,氟橡胶含量通过分子间静电力作用对复合粒子微观形貌产生影响。

To reveal the coating mechanism of fluorine rubber(F2604)on nano-aluminum powder(n-Al),by using electrostatic spray technology,the composite particles with different content of F2604 were prepared in different solvents(ethyl acetate and acetone).The morphology of the composite particles was characterized by scanning electron microscope(SEM).The influence of solution parameters on the micro-morphology of nano-Al/F2604 composite particles was studied by means of experiment and molecular dynamics simulation.Results show that acetone as a solvent can make the composite particles more uniform and regu-lar in morphology.When the content of fluorine rubber is less than 13%,the particle diameter increases with increasing the pro-portion of fluorine rubber.When the content of fluorine rubber continues to increase,the particle size distribution of composite particles becomes uneven.The shape is irregular and obvious spinning phenomenon is appeared.The diffusion coefficient of fluo-rine rubber in the solvent is one of the important factors affecting the molecular chain morphology when coating nano-aluminum powder using fluorine rubber,thus the principle of“large diffusion coefficient of fluorine rubber”should be followed when se-lecting solvents.The unit binding energy between fluorine rubber and nano-aluminum powder is mainly composed of electrostat-ic interaction energy(75%-93%)and van der Waals interaction energy(6%-22%).The effect of fluorine rubber content on the micro-morphology of composite particles is affected by intermolecular electrostatic interaction.