Synthesis And Performance Research Of Polymer Brush Grafting Magnetic Nanocomposites

Magnetic nanomaterials possess not only the general properties of ordinary nanomaterials but also the special magnetic properties,which provides them the potential applications in the fields of environmental analysis,biomedicine and separation.Among numerous magnetic nanomaterials,Fe3O4 nanoparticles has been paid plenty of attention owing to its superparamagnetism and well biocompatibility.However,the interaction among traditional magnetic nanoparticles leads to the appearance of agglomeration,which could destroy the steady state of the magnetic nanoparticles.Surface modification of magnetic nanoparticles could efficiently prevent the agglomeration tendency and make it easily for endowing the magnetic nanoparticles with multiple functions by the second modification.Therefore,amounts of magnetic nanocomposites have been prepared for a variety of purposes.In this thesis,high density polymer brashes grafting magnetic nanocomposites with typical "core-brush" nanostructure were synthesized by combing surface initiated atom transfer radical polymerization(surface initiated atom transfer radical polymerization,SI-ATRP)technique and second functional modification.The obtained magnetic nanocomposites were applied for selective adsorption of dye,efficient removal of heavy metal ions and catalysis of dye degradation,respectively.The procedure of magnetic nanocomposites preparation was monitored by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)and so on.Detailed investigation was followed:1.A novel magneticnanocomposite(Lys-PGMA@Fe3O4)containing amphoteric polymer brashes was synthesized by combining SI-ATRP and lysine modification.The chemical structure of Lys-PGMA@Fe3O4 was confirmed by multiple methods,such as FT-IR,TGA,elemental analysis.The core-brush morphology was clearly observed by transmission electron microscopy.Lys-PGMA@Fe3O4 was then used to selectively and efficiently adsorb hazardous dyes.Adsorption results showed that Lys-PGMA@Fe3O4 had considerable adsorption capacityand rapid adsorption rate,which can be attributed to the nanosize and abundant adsorptive polymer brushes.The selective adsorption of a mixture of lemon yellowand methylene blue was achieved through the amphoteric polymer brushes.Similar to traditional adsorbent materials,Lys-PGMA@Fe3O4 also showed easy magnet-assisted separation property.Lys-PGMA@Fe3O4 adsorbent can also be regenerated to reduce application cost.Overall,results demonstrated that Lys-PGMA@Fe3O4 nanocomposite was an excellent adsorbent material for removing dye pollutants from wastewater.Besides,the treatment of oily sewage by Lys-PGMA@Fe3O4 was investigated.2.A novel magnetic nanocomposite(TREN-PGMA@Fe3O4)containing was synthesized by combining SI-ATRP technique and tris(2-aminoethyl)amine(TREN)modification,which was finally applied in efficient adsorption for hazardous heavy metal ions.The chemical structure of TREN-PGMA@Fe3O4 was confirmed by multiple methods,and the core-brush morphology was clearly observed by SEM.More importantly,the adsorption results showed that TREN-PGMA@Fe3O4 has considerable adsorption capacity and rapid adsorption rate,which can be attributed to the nanometer size and abundant adsorptive polymer brushes.Compared with traditional adsorbent materials,TREN-PGMA@Fe3O4 also showed facile magnetic assistant separation property.Additionally,TREN-PGMA@Fe3O4 adsorbent can be regenerated for reducing application cost.The results demonstrated that TREN-PGMA@Fe3O4 nanocomposite could serve as an excellent adsorbent material for removing dye pollutants from wastewater.Besides,the treatment of oily sewage by TREN-PGMA@Fe3O4 was investigated.3.Poly 2-(Dimethylamino)ethyl methacrylate(PDMAEMA)polymer brashes were grafted onto the surface of Fe3O4 magnetic nanoparticles modified with poly-dopamine.The magnetic nanocomposites Pd-EtBr-PDMAEMA@Fe3O4 was synthesized by in situ growth of Pd nanoparticles on the surface of nanomaterial after the second modification by EtBr.The chemical structure,"core-brush" nanostructure and magnetic properties were investigated by FT-IR,TGA,Elemental Analysis,XPS,TEM and so on.Compared with the ordinary Pd nanoparticles,magnetic nanomaterial Pd-EtBr-PDMAEMA@Fe3O4 displayed a much better catalysis behavior in the reaction of MEB degradation by NaBH4 because the PDMAEMA polymer brushes improved the dispersity of Pd nanoparticles in water,and increased the contact area between the catalyst and reactants.Besides,Pd-EtBr-PDMAEMA@Fe3O4 can be regenerated for reducing application cost.