Preparation And Characterization Of SrFe₁₂O₁₉/NBR Magnetic Rubber Nanocomposites

In the present work, the preparation and surface modification of SrFe₁₂O₁₉ magnetic nanoparticles and SrFe₁₂O₁₉/NBR magnetic rubber nanocomposites were studied. In the part of the preparation of SrFe₁₂O₁₉ magnetic nanoparticles, the effects of Fe/Sr molar ratio, calcination temperature and amount of flux on magnetic properties were investigated in details; In the part of the surface modification of SrFe₁₂O₁₉ magnetic nanoparticles, the research content mainly involved the effect of the modification with the type and amount of surfactant and relevant characterization. The surface modified SrFe₁₂O₁₉ magnetic nanoparticles were incorporated into NBR to prepare SrFe₁₂O₁₉/NBR magnetic rubber nanocomposites, The effects of different amount of carbon black and plasticizer DOP on the mechanical properties of based-rubber were studied separately. the mechanical and magnetic properties of magnetic rubber nanocomposites were evaluated through different types of surfactants modified SrFe₁₂O₁₉ magnetic nanoparticles and different magnetic nanoparticles, and the anti-aging properties of magnetic rubber were researched and improved.The results showed that the SrFe₁₂O₁₉ magnetic nanoparticles prepared by chemical coprecipitation route and molten and salt method possessed high purity, regular morphology and excellent magnetic properties. The results of infrared testing, contact angle measurements and SEM observations indicated that silane coupling agent Si69, titanium coupling agent TM-200s and TM-38s had chemically reaction with the surface of SrFe₁₂O₁₉ particles, which improved the compatibility with mocromolecules, and the action mechanism of interaction of SrFe₁₂O₁₉ particles and the polymer material in the role of TM-200s were studied preliminarily, taking TM-200s for example.The results of physical mechanical properties of rubber showed that rubber tensile strength and elongation at break increased and then decreased with the increase of the carbon black content, and the rubber obtained the best physical mechanical properties when the carbon black content was 40 copies. With the increase the DOP amount, the tensile strength and modulus decreased gradually within a small area, the elongation at break increased and then decreased, and the rubber had the best physical mechanical properties when the DOP content was 40 copies. Coupling agent Si69 and titanium coupling agent TM-38s could effectively improve the compatibility of SrFe₁₂O₁₉ particles and rubber, thus greatly improving the mechanical properties of magnetic rubber. With the increase of the content of SrFe₁₂O₁₉ particles, magnetic rubber elongation at break decreased, modulus increased, while the tensile strength increased first and then decreased, indicating that SrFe₁₂O₁₉ particles had inforced effect though adding small doses. The magnetic particles destroyed the network of carbon black and the NBR chain structure, which led to a substantial decline in the mechanical properties of magnetic rubber when adding high quantity of copies, magnetic results of magnetic rubber showed that saturation magnetization and residual magnetization of magnetic rubber gradually increaseed with the addition of SrFe₁₂O₁₉ particles, while coercive force remained unchanged.The anti-aging properties of magnetic rubber had been greatly improved by increasing a small amount of antioxidant 4010NA, antioxidant RD, and liquid paraffin, thereby SrFe₁₂O₁₉/ NBR magnetic rubber nanocomposites were prepared with excellent physical mechanical properties, aging properties and magnetic properties.