【作者】 陈祥凤；

【导师】 董星龙；

【作者基本信息】 大连理工大学 ， 材料物理与化学， 2009， 硕士

【摘要】 磁性纳米粒子是一种良好的微波吸收材料,将磁性金属纳米粒子加入到聚合物基体中,可以使得复合材料既具有磁性纳米粒子的性能又具有聚合物基体的性能。然而磁性纳米粒子易团聚、化学稳定性差、与有机介质相容性差,极大的影响了其应用发展。因此选用合适的材料对磁性粒子进行表面改性,不仅能防止磁性纳米粒子的氧化和团聚,而且可以提高磁性纳米粒子与聚合物基体的相容性。本文主要研究了聚苯胺/镍纳米复合材料的制备与表征以及磁性吸波剂纳米铁粉、碳包覆铁纳米粉加入到水性丙烯酸树脂涂料制备的水性纳米复合涂料的吸波性能。采用界面聚合的方法制备聚苯胺,通过改变上、下界面的反应溶剂和反应温度等工艺参数制备了形状比较均一的管状聚苯胺。同时采用界面聚合法制备了管状聚苯胺/镍纳米复合材料,通过FT-IR、XRD、TEM分析表征表明,生成了管状聚苯胺,形状均一,直径大约在100nm,并且存在着部分的结晶。聚苯胺很好地包覆了纳米镍粉,实现了管状聚苯胺及聚苯胺包覆纳米镍粉的多种物质及形态的复合,对其制备工艺及微波频段的电磁特性进行了研究。以“壳/核”型碳包覆铁(Fe(C))纳米颗粒为填料,水性丙烯酸树脂为基体制备了纳米复合电磁波吸收涂料。采用不同含量十二烷基苯磺酸钠(SDBS)对纳米颗粒改性,提高了纳米颗粒在基体中的分散性。选用吸收剂填充量为30wt%的涂料,测定了不同厚度涂层的电磁波吸波性能。涂层具有很好的吸波性能,当厚度为5mm时,反射损耗峰值为-17.2dB,吸收带宽为3.2GHz(7～10.2GHz)。实验结果证明了传输线理论对铁磁性纳米颗粒吸波性能的模拟结果。并制备了3mm的不同含量的涂层测定其吸波性能。以铁(Fe)纳米颗粒为填料,水性丙烯酸树脂为基体制备了纳米复合电磁波吸收涂料。采用钛酸酯偶联剂(JSC)对纳米铁粉进行表面处理,提高其与丙烯酸树脂的相容性。选用吸收剂填充量为30wt%的涂料,测定了不同厚度涂层的电磁波吸波性能。涂层具有很好的吸波性能,当涂层厚度为3mm时,在2～18GHz频段内吸收优于-10dB的频宽则约为2.3GHz(5.9～8.2GHz)。更多还原

【Abstract】 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).更多还原