Preparation And Ultrasonic Performance Testing Of Multifunctional Magnetic Nanocomposite Microspheres

Magnetic nanoparticles have stable chemical properties,good magnetic responsiveness and biocompatibility ect.Its have been widely used in adsorbent,coating,catalyst and biological sensing cell tracking,magnetic resonance imaging(MRI),targeted drug delivery and cancer therapy ect.Polymer has attracted more attention due to the advantages of many functional groups on the surface and great hydrophilism.Thermosensitive polymer materials based on N-isopropylacrylamide(PNIPAM)have attracted much attention in many fields such as drug delivery,biosensor and macromolecular separation ect.However,such polymer materials do not possess magnetic responsiveness.Special polymers,such as temperature,PH sensitivity,etc.are combined with magnetic materials to meet the requirements.Therefore,Magnetic polymer composites have appeared and been applied.Composite materials have many characteristics of polymer materials and magnetic responsiveness,which bring more convenient conditions for binding biomolecules,and promote the development of biological technology.Therefore,the magnetic polymer composite microspheres have very important research value in biosensor,medical treatment,detection and magnetic separation ect.With the rapid development of radar,electronic countermeasures and sonar technology,the application of microwave absorbing materials is more and more extensive,and has attracted more researchers' attention.Because the materials made of single material are difficult to meet the requirement of thin thickness,light mass and absorption frequency bandwidth.The unique viscoelasticity,easy processing and high performance price performance of polymer composites make it very important for the study of absorbing materials.In this paper,we modify the surface of Fe3O4 nanoparticles and then coat the N-isopropylacrylamide(PNIPAM)polymer materials to form PNIPAM@SiO2@Fe3O4 magnetic nanocomposites,and the ultrasonic characteristics of the composite were detected.The primary contents are as following:(1)Nano Fe3O4 microspheres were prepared by hydrothermal method.SiO2 were coated on magnetic Fe3O4 particles by improved Stober method,which finally resulted in SiO2@Fe3O4nano magnetic composite.(2)The surface of SiO2@Fe3O4 nano magnetic composite microspheres was modified by MPS chemical reagent,make its surface with C=C,which finally come to the PNIPAM@SiO2@Fe3O4 composite microspheres with superparamagnetic.(3)Gelatin was used as the fixing material for samples.The gelatin solid was properly heated and dissolved,adding PNIPAM@SiO2@Fe3O4 magnetic nano-composite microspheres into gelatin aqueous solution and glutaraldehyde was added at room temperature.Finally the ultrasonic properties of the composite material were detected.Several techniques,e.g.Transmission Electron Microscope,Scanning Electron Microscope,Infrared Spectrometer,Vibrating Sample Magnetometer,Thermogravime-tric Analyzer etc.were used to characterize structures and properties of the composites.In conclusion,the composites are good core-shell structure,regular spherical,uniform particle dispersion,exhibiting good morphology and excellent superparamagnetism.5057PR Ultrasonic Pulse Transmitter and Receiver,Ultrasonic Testing Probe(PA NAME TRICS A126S),Digital Oscilloscope(DS1052E)etc.were used to detect the ultrasonic properties of the composite material.In summary,Composite materials has an obvious absorption effect on the ultrasonic wave,so the composite material can be used in the field of absorption and shock absorption.