Conductive Polymer Composite Nano Materials Preparation And The Research Of Electromagnetic Performance

In recent years the study of conductive polymer nanocomposites becoming a researchhotspot,at home and abroad.Polymer nanocomposites of polyaniline, polypyrrole formed bypolymer and metal, metal oxide, semiconductor nanoparticles have been reported. Conductivepolymer and magnetic nanoparticles compositing to develop electro-magnetic material is animportant way for preparation of electromagnetic shielding materials and electromagnetic waveabsorber materials, which can realize composite electromagnetic properties.And we not only canadjust electric, magnetic properties of composite materials,but also can make up for thedisadvantages of difficultiesof forming inorganic nano-material.We prepared doped ferrite powder by Sol-gel method, and then prepared Lanthanumdoping nickel copper zinc ferrite and polyaniline composite material, lanthanum doped bariumferrite-poly methyl composite material, lanthanum doped barium ferrite-poly3-methylthiophene composite materials and detereted the structure,electromagnetic characterization Byusing X-ray diffraction （XRD）, infrared spectroscopy （FT-IR）, electron microscopy （TEM）andvibrating sample magnetometer （VSM）.The concrete research contents and results are asfollows:1. Ni_0.25Zn_0.5Cu_0.25La_xFe_2-xO₄（x=0、0.05,0.1,0.15,0.2） and Ni_0.5-yZn_0.5Cu_yLa_0.05Fe_1.95O₄（y=0,0.05,0.1,0.15,0.2） were synthesized by sol-gol method, under calcination for2h at850℃,950℃and1050℃, respectively. The n, the composites were prepared by in situ method. XRDindicated that when the calcination temperature was at850℃, the ferrite was coated easily bypolyaniline. When the calcination temperature was at1050℃, the impurities and intermediateswere reduced. And with the increasing of the calcination temperature, the particle size of ferriteincreased. FT-IR showed that there some interfactions between polyaniline and ferrite. TEMshowed that the shape of composites was spherical. With the increasing of the content of Cu inferrite, the size of ferrite decreased firstly and then increased. When the calcination temperaturewas at1050℃, the size of composites was at66.7nm. And the size of composites was62.5nmat850℃. Conductivity test showed that when the calcination temperature was at850℃, theconductivity of the composites achieved4.012S/cm higher than the composites at1050℃. VSManalysis indicated that when the calcination temperature at850℃, the saturation magnetizationof composites reached22.67emu/g stronger than the composites at1050℃.2.The La-doped BaLa_XFe_12-XO₁₉（X=0.00,0.04,0.08,0.12） powders were prepared throughsol-gol method. The La-doped Ba-ferrite/poly-p-toluidine composites were synthesized by in situ method with ammonium persulfate oxidant around the hydrochlorie acid. At the same time,poly-p-toluidine was prepared through chemical oxidation method. XRD test showed that thedoped La didn’t change the structure of the parent ferrite. FT-IR analysis showed that there weresome interfactions between ferrite and poly-p-toluidine. TEM showed that the size of La-dopedBa-ferrite was at about80nm, and the size of the La-doped Ba-ferrite/poly-p-toluidinecomposites was at about300nm. Conductivity analysis showed that the content of La was notlarge impact on the conductivity of the composites; VSM analysis shows that, when the contentof La was0.12, the saturation magnetization of composites reached6.58emu/g.3.Six angle with M lanthanum doped barium ferrite BaLa_XFe_12-XO₁₉was prepared by usingsol-gel technique and self-propagating combustion method.The Effections of citric acid, pHvalue,polyethylene were an analysised According to the analysis of the mechanism ofagglomeration. Ultimately the conditions of preparing M type barium ferrite weredetermined,which is acid and metal ion ratios of1:1, pH weak acid, polyethylene （2g）. Then,La-doped Ba-ferrite/poly（3-methylthiophene） composites were prepared by La-doped Ba-ferriteand Poly（3-methylthiophene） through chemical oxidation polymerization method. XRDindicated that, among BaLa_xFe₁₂O₁₉（x=0,0.04,0.08,0.12） samples, when X=0.08, Fe3+wasreplaced by La3+in composites without miscellaneous peaks. FT-IR showed taht there were someinteracctions between La-doped Ba-ferrite and poly（3-methylthiophene）. Conductivity testsshowed that the composite conductivity increased with the increasing of the content of La-dopedchanged in the conductivity of the composite. The conductivity of composites reached4.235S/cm. VSM analysis showed that the La-doped barium ferrite maked a great impact, inimproving barium ferrite coercivity, increasing the residual magnetization, strengtheningsaturation magnetization and hysteresis loss. And the poly（3-methylthiophene） wasnomagnetic.