Study On The Synthesis Of Polymer Cross-linked Magnetic Composite Microspheres

In recent years, the development of polymer materials trends to behigh-performance and multi-function, special properties of polymer compositemicro-spheres have been attracting much attention for their extensiveapplications in many domains. Nanometer magnetic materials are well closelylinked with the areas of information, automatization, economy and so on.Controlled synthesis and assembly of nanometer magnetic materials is currentlythe subject of intense research work due to their novel properties, which couldhave promising applications, such as high-density magnetic recording media,sensors, catalysts, biotechnology, and magneto-optical devices and so on. Inparticular, it has been attracted much attentions in the fields of biotechnologyand high-density magnetic recording media that the use of the nanometermagnetic materials. Therefore, scientists made abroad interests on the study ofnew nanometer magnetic materials and nanometer magnetic compositesmaterials. The application of nanometer magnetic materials which containnano-magnetic particles and polymer materials has instructive significance intheory and practice.The nanometer magnetic materials are very important nanometer materials.Nanometer magnetic materials have a lot of excellent properties: â‘  thediameter is between 1nm and 100nm;â‘¡ the surface contains the shell ofpolymer, which is all through a focus of material science to introduce functionalgroups onto latex particles;â‘¢ the surface can be modified, the shell ofpolymer has functional groups, so we can put the polymer materials of thebiology and medicine into the surface of the magnetic particles;â‘£ it hassuperparamagnetic property. As its diameter is small, is exhibits specialproperty, such as magnetic property. It could have promising applications, suchas cell separation, or as pigments, catalysts, coating, flocculents, toners, etc.The magnetic composite micro-spheres consisted of organic copolymerand in-organic particles. Different from pure polymer and pure in-organicmaterials, the particles systems exhibit many special properties in density,magnetism, mechanics and fluidity, and be widely used in the fields of medicalscience, biology, magnetic materials, biotechnology, mechanical and electricaldevices et al. The magnetic micro-sphere is generally the structure of core-shell,magnetic particles are homogeneously encapsulated in a hydrophobic polymer,which keep away water-soluble components from the magnetic particles .It always would be focus of the material science to put the functionalgroups into the surface of the magnetic composite micro-spheres. Themono-disperse magnetic cross-linked composite micro-spheres containingcarboxyl groups have been prepared by an improving method of emulsionpolymerization in this paper. The mono-disperse magnetic cross-linkedcomposite micro-spheres were obtained in aqueous, and consisted of thecopolymer of styrene and acrylic acid as shell and the Fe3O4 magneticnano-particles as core.To modify the inclination of conglomeration of magnetite in dispersephase and increase magnetic content of composite particles, oleic acid was usedfor the surface modification of magnetite. Acrylic acid was used as co-monomerto further improve the combination of magnetite with polymer particles. Thesize and coating morphology of magnetic composite micro-sphere could beadjusted by varying some parameters of emlusion polymerization. Thefunctional particles and core-shell composite micro-sphere were characterizedby IR,XRD, TG,TEM and XPS.In this paper, we studied the preparation of the Nano-sized, mono-disperse,cross-linked, magnetic composite polymer micro-spheres. There is fewliterature of the cross-linked, magnetic composite micro-spheres at the presenttime. This kind of the cross-linked, magnetic composite polymer micro-sphereswill have a lot of excellent properties compared with the common cross-linkedmicro-spheres: (1) the size distribution of the micro-spheres is uniform and thediameter of it can control easily;(2) this kind of the cross-linked micro-spherescan keep excellent stability in in organic and inorganic solvent for a long time;(3) the magnetic composite polymer micro-spheres exhibit many specialproperties including their magnetic properties, mechanical properties andfluidity are different from pure polymer and pure in-organic materials. So theycan be applied in many fields including medical science, biology, magneticmaterials, biotechnology, mechanical and electrical devices et al. We can drawa conclusion that: the magnetic cross-linked micro-spheres can be the rudimentof the magnetic nano-network, this paper may be helpful in the study of themagnetic nano-network deeply, the detail of the research of the magneticnano-network will continue to be discussed in future work.