Preparation And Characterization Of M-type Nano-Strontium Ferrite/Conductive Polymer Composite

In the paper,two methods were applied in the preparation of SrFe12O19.One was original sol-gel method,and the other was the cotton template sol-gel method.Then SrFe12O19/PANI and SrFe12O19/PPY composites were synthesized using the two kinds of ferrite.The testing technologies such as XRD,FTIR,TEM,SEM,VSM and so on were used to study the effect of the material component,the types of surface treatment agent,the structure and morpholgy on the electromagnetic properties of samples.The conclusions were as follows:1,The sphericity nano-SrFe12O19 was synthesized by original sol-gel method.And the flocs-like nano-SrFe12O19 with the excellent magnetic property was synthesized using cotton as template by sol-gel method.From the analogy of the two kinds of nano-SrFe12O19, a conclusion can be come to that the coercive force,the saturation magnetization and residual magnetization of samples obtained by cotton template sol-gel method were superior to the samples obtained by original sol-gel method.The coercive force,the saturation magnetization and residual magnetization of samples were improved by 7%,40% and 20% respectively.The machanism of the phenomenon was studied.2,The sphericity nano-SrFe12O19 obtained by original sol-gel method was used as inorganic phase to synthesize the core-shell structure PANI/ SrFe12O19 composite.Through the systemly studies onto the electromagnetic properties of the samples,it can be found that the the variation was nonlinear as the variation of the SrFe12O19 content.The saturation magnetization (Ms) and remanent magnetization (Mr) for the PANI/nano-SrFe12O19 composites exhibited a decrease with the decreasing of the nano-SrFe12O19 content in the system. The coercivity force (Hc) for the PANI/nano-SrFe12O19 composites were higher than the values measured from bulk magnetite when the content of PANI was at a low scale, and decreased with the increase of PANI content. When the PANI content came to a critical value, the coercivity force (Hc) for the PANI/nano-SrFe12O19 composites became lower than the values measured from pure nano-SrFe12O19. The possible mechanism for the phenomena had been proposed in the paper. The conductivity of the PANI–SrFe12O19 composites increased with the increase of SrFe12O19 content in the composites firstly, and then decreased with the increase SrFe12O19 content.3,The sphericity nano-SrFe12O19 obtained by original sol-gel method was used as inorganic phase to synthesize the core-shell structure PPY/ SrFe12O19 composite.Through the systemly studies onto the electromagnetic properties of the samples,it can be found that the variation was nonlinear as the variation of the SrFe12O19 content.The saturation magnetization (Ms) and remanent magnetization (Mr) for the PPY/nano-SrFe12O19 composites exhibited a decrease with the decreasing of the nano-SrFe12O19 content in the system. The coercivity force (Hc) for the PPY/nano-SrFe12O19 composites were higher than the values measured from bulk magnetite when the content of PPY was at a low scale, and decreased with the increase of PPY content. When the PPY content came to a critical value, the coercivity force (Hc) for the PPY/nano-SrFe12O19 composites became lower than the values measured from pure nano-SrFe12O19. The conductivity of the PPY–SrFe12O19 composites increased with the increase of SrFe12O19 content in the composites firstly, and then decreased with the increase SrFe12O19 content. The possible mechanism for the phenomena had been proposed in the paper.4,The flocs-like nano-SrFe12O19 obtained by original sol-gel method was used as inorganic phase to synthesize the PPY/ SrFe12O19 composite.Different surface treatment agents were used to improve the surface properties of SrFe12O19. .Through the systemly studies onto the electromagnetic properties of the samples obtained by different surface treatment method, it can be found that the conductivity of the PPY–SrFe12O19 composites obtained by The conductivity of the PPY–SrFe12O19 composites obtained by sodium lauryl benzenesulfate was superior to that by cationic surfactant and KH-570.The coercive force,the saturation magnetization and residual magnetization of samples obtained by sodium lauryl benzenesulfate was superior to that by cationic surfactant.However the magnetization of samples obtained by KH-570 was superior to that obtained by sodium lauryl benzenesulfate and cationic surfactant.The magnetization of the sample was improved by 400%.By further excellent blending, which can make high performance absorbing materials to meet practical requirements, and give further research of Nano-SrFe12O19/conductive polymer electromagnetic microwave absorbing materials.