| Nanocomposites have both the advantages of nanomaterials and composite materials,so they have received extensive attention and application in various industries.Nanocomposite energetic materials have many advantages,such as high energy density,high release rate and efficiency,short ignition delay time and so on,which have been widely used in military and civil applications.Since the nanoparticles have a large surface area,resulting in the particles are easy to aggregate,the contact area between the reactants is reduced,its application is limited.Some new method for preparing a nanocomposite material capable of containing the oxidizing and reducing reaction and sufficiently mixed,to improve the thermal properties of nano-composite energetic materials.In this paper,CuO/Al nanocomposite energetic materials were prepared by DNA self-assembly method.The optimized micro-morphology and high thermal properties of the samples were obtained by optimizing the conditions,and the thermal reaction mechanism of nanocomposite energetic materials was explored.The main research work and conclusions are as follows:?1?Nanocomposite energetic materials assembled by DNA mainly include three parts:preparation of nanodispersion system,biomolecular modification of nano-materials?avidin-modified nano-materials,DNA-grafted nanomaterials?,and assembly of nanocomposite energetic materials.Preparation of nanodispersion system:the optimum condition for preparing CuO nanodispersion system is 0.8 mg/mL 0.01 M PBS+0.05 wt%Tween-20,ultrasonic treatment time is 12 min;The optimum condition of nano-Al dispersion system was 0.8 mg/mL 0.01 M PBS+0.05 wt%Tween-20,ultrasonic treatment time is 10 min.?2?Biomolecular modification of nanomaterials:the optimal conditions for incubation of nanomaterials with avidin that the concentration of avidin was 0.007mg/mL(1.03×10-7 M),and the incubation time was 24 hours;the optimal conditions for DNA grafted nanomaterials that the concentration of was 9×10-7 M DNA and the incubation time was 2 hours.The adsorption of biomolecules on the surface of nanoparticles was qualitatively characterized by Fourier Transform Infrared spectroscopy?FT-IR?.The particle size and surface charge of nanoparticles was characterized by nano-laser particle size analyzer?Nano-ZS?.The adsorption of biomolecules on the surface of nanoparticles was studied by ultraviolet spectrophotometer?UV?.The microstructure of nano-materials modified by biomolecules was characterized by electron microscopy?SEM and TEM?.The mechanism of avidin modification on the surface of nano-materials was studied by fluorescencespectrophotometer,ultravioletspectrophotometerandX-ray photoelectron spectroscopy?XPS?,and the interaction mode of DNA grafted onto the surface of nano-materials was also analyzed.?3?Assembly of nanocomposite energetic materials:the volume of the nanomaterials of the DNA grafted was mixed and incubated to obtain the CuO/Al nanocomposite energetic material,and the DNA self-assembled sample was compared with the physical sample.The microstructure of nano-materials was characterized by scanning electron microscope and transmission electron microscope.The kinetics of the DNA assembly process was studied by nano-laser particle size analyzer?Nano-ZS?.The reaction heat of the samples was tested by differential scanning calorimeter?DSC?.The preparation process of nanocomposite energetic materials is affected by many factors.The salt concentration,enthalpy value and nanoparticle size can significantly affect the microstructure and reaction properties of nanocomposite energetic materials,mainly exploring the above three factors for nanocomposite energetic materials.The influence of structure and properties,and optimization of experimental conditions for nanoparticles of different particle sizes gave better micromorphology.?4?Microstructure and crystal forms of the intermediate products were studied by transmission electron microscopy?TEM?and X-ray diffraction?XRD?at different heating temperatures and the aluminothermic reaction mechanism of nanocomposite energetic materials was obtained.The reaction of CuO/Al nanocomposite energetic materials is mainly the reaction of Cu2O at low temperature to form Cu with the increase of temperature,and finally the crystal form conversion. |
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