The Preparation And Microwave Absorption Properties Of The Composite Of Metal-based Nanoparticles/polymer

Magnetic metal nanoparticles are considered as a kind of excellent microwave absorbers. However,the applications of the nanoparticles are limited by some factors,such as agglomeration,poor chemical durability and combination with organic matrix.Selecting proper organic surfactants to modify nanoparticles can solve agglomeration in polymer, improve the compatibility of organic compounds.Adding the magnetic metal nanoparticles into the polymer make the nanocomposites not only have the properties of nanoparticles but also the polymer.In this paper,the preparation and properties of tube-polyanilin/polyaniline coated nano-nickel(PANi/PANi(Ni)) nanocomposites are studied.As well as,the nano-iron/ waterborne acrylic resin and carbon coated iron/waterborne acrylic resin nanoconposites were researched,and the characteristics of them also were studied.The tube-polyaniline is prepared by a simple interracial polymerization method through change the aqueous/organic biphasic system and reaction temperature.As well as the tube-polyanilin/polyaniline coated nano-nickel(PANi/PANi(Ni) nanocomposites are prepared. Both samples are characterized by Fourier transform infrared spectroscopy,X-ray diffraction (XRD) and transmission electron microscope(TEM).The results show that the PANi is tubal with diameter of about 100nm and length of several micrometers,and exhibits some crystalline grains of several nanometers on the surface.In the system of PANi/Ni nanocomposite,it can also be found the PANi tubes and almost all the Ni nanoparticles encapsulated into PANi shells,exhibiting a coexistence of two kinds of morphologies.The microwave characteristics of both samples are measured and discussed in detail in this paper.The microwave absorption properties of the coatings containing 30wt%of the carbon-coated Fe nano-particles with various thicknesses was tested,in which the waterborne acrylic resin was used as the matrix.To improve the dispersion of the nano-particles in resin, sodium dodecyl benzene sulfonate(SDBS) was employed as the surfactant.The results showed that the coatings have excellent absorbing properties in thickness of 5mm,presenting the reflection loss of -17.2dB at 8.6GHz and the bandwidth of -10dB at 3.2GHz(7～10.2GHz). Based on the current results,it was confirmed that the absorption properties of ferromagnetic nano-particles are basically consistent with the theoretical prediction of transmission line.As well as the microwave absorbing properties of the coatings which thickness is 3mm containing different contant of carbon-coated Fe nano-particles were tested.The microwave absorbing properties of the coatings containing 30wt%of the nano-Fe with various thicknesses was tested,in which the waterborne acrylic resin was used as the matrix.To improve the compatibility of the nano-particles in resin,titanate coupling reagent (JSC) was employed as the surfactant.The results showed that the coatings have excellent absorbing properties in thickness of 3mm,presenting the bandwidth of -10dB at 2.3GHz (5.9～8.2GHz).