Polymeric Magnetic Nanocomposites Via Radical Bulk Polymerization

In recent years, polymeric magnetic nanocomposites have become one of the hottest research topics in material field. Combining the advantages of the polymer matrices and the inorganic magnetic nanometer material, the polymeric magnetic nanocomposites could be applied in various fields such as electro-magnetic shielding, adsorbents, catalysts, and so on.Due to the advantages of high purity, high performance, high equipment utilization rate, simple operation without complex separation and purification of the bulk polymerization technique, it can be used for the mass production of the polymer nanocomposites. In the thesis, the bulk polymerization technique is used for the preparation of the polymer magnetic nanocomposites. Furthermore, the synergetic dispersion strategy is developed for the polymer-based tri-component nanocomposites containing two kinds of the inorganic nanomaterials via the "one-pot" bulk radical polymerization technique. The properties of the polymer-based tri-component nanocomposites prepared are also investigated.1. The Fe3O4/polystyrene magnetic nanocomposites are prepared by in situ solution polymerization with the oleic acid modified Fe3O4nanoparticles as fillers firstly. The grafting percentages of the polystyrene onto the magnetic nanoparticles with different feeding ratio are compared. Then the Fe3O4/polystyrene magnetic nanocomposite is prepared vai the bulk radical polymerization technique under the optimized feeding ratio. The dispersion of the Fe3O4nanoparticles in the polymeric matix and the magnetic, thermal stability of the Fe3O4/polystyrene magnetic nanocomposite are investigated.2. Novel fly ash/polystyrene (FA/PS) composites with crosslinking structure were prepared via the facile in-situ "one-pot" radical polymerization in the present of y-methacryloxypropyl trimethoxy-silane (KH570) as coupling agent. The effect of the amount of FA added and the role of the coupling agent on the properties of the FA/PS composites were investigated via the thermal analysis and swelling technique. Their structural model was proposed on the basis of the thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and swelling analysis. The magnetic properties of the FA/PS composites were also investigated. The technique developed in the present work is expected to be used for the mass production of low-cost magnetic crosslinked polymer-based composites.3. The synergetic dispersion strategy is developed for the polymer-based tri-component nanocomposites containing two kinds of the inorganic nanomaterials via the "one-pot" bulk radical polymerization technique. Here, the magnetic nanoparticles are immobilized onto other inorganic nanomaterials to form the magnetic inganic composites. It could avoid the aggragation of the magnetic nanoparticles in organic matrices due to their magnetic peroporty. Then the magnetic inganic composites are surface-modified with oleic acid to improve their dispersibility in organic matrices. The polystyrene could be grafted onto the magnetic inganic composites via the copolymerization of the monomer (styrene) and the oleic acid modified on the magnetic inganic composites. So the polymer-based tri-component nanocomposites with good interfacial property could be obtained easily.In the section, attapulgite, carbon nanotubes, and graphene with three different morphologies such as nanorods, nanotubes and nanosheets are selected as the inorganic supports. It is found that the better interfacial performance could be achieved with the carbon nanomaterials (carbon nanotubes and graphene) as the supports, due to the grafting of the polystyrene chains via the radical addition reaction.The mechanical properties of the polymer-based tri-component nanocomposites via the synergetic dispersion strategy are compared with the corresponding tri-component nanocomposites prepared by the independently adding the magnetic nanoparticles and the inorganic nanomaterials. It could be concluded that the polymer-based tri-component nanocomposites via the synergetic dispersion strategy exhibit the higher mechanical performance. The better interfacial property resulted from the synergetic dispersion strategy could be seen by the fracture surfaces with the SEM technique.