Study On The Synthesis And Properties Of Functional Poly Methyl Methacrylate Composite Microspheres

Polymer microspheres material is a spherical micro-nano composite whichsynthesized with monomer or polymer materials. Compared to the conventional polymermicrospheres material, special functional polymer microspheres have attracted tremendousattention to scientists in chemical, biological, pharmaceutical, telecommunication and otherfields, due to their unique properties, such as large specific surface area, high surfaceactivity, controllable structure and good adsorption performance.In this study, the synthesis and properties of functional poly methyl methacrylate(PMMA) composite microspheres were extensively investigated. Carboxyl functional,amino functional and organic-inorganic with core-shell structure PMMA compositemicrospheres were synthesized by different polymerization methods. The size, morphology,structure and performance of the PMMA composite microspheres were characterized andanalyzed by infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-raydiffraction (XRD), energy dispersive spectrometer (EDS), fluorescence analysis (FS) andso on. The main research work contents include the following aspects:a) The preparation of PMMA microspheres with different particle sizes: PMMAmicrospheres were prepared by dispersion polymerization and emulsion polymerization,the particle size of the obtained microspheres was800nm and200nm, respectively. In thedispersion polymerization, study work was focused on the effects of monomer content,initiator amount, dispersing agent volume, medium ratio on particle size and distribution.b) The research of carboxyl-functionalized PMMA microspheres: methyl methacry late(MMA) and acrylic acid (AA) were used as the first monomer and second monomerrespectively to prepare crosslinked P(MMA-AA) microspheres with carboxyl functionalgroups on the surface. The effect of the addition of AA on the surface carboxyl content wasstudied. The ester group of PMMA and P(MMA-AA) microspheres were hydrolyzedthrough saponification reaction in order to improve the content of surface carboxyl group.The carboxyl content of different microspheres were measured by conductance titration,the P(MMA-AA) microspheres can be promoted to0.26mmol/g.c) Preparation and properties of PMMA composite microspheres with amine groups:Amine monomer selected allylamine hydrochloride (AH) and acrylamide (AM), compositemicrospheres of P(MMA-AH), P(MMA-AM) and P(MMA-AH-AM) were obtained bysoapfree emulsion polymerization, dispersion polymerization and inverse emulsion polymerization, respectively. The phosphate adsorption capacity of different microsphereswere investigated, the results show that P(MMA-AH-AM) microspheres have maximumphosphate adsorption capacity, up to647μg/g, the adsorption capacity of amino was moresignificant than amide group.d) Synthesis and characterization of inorganic-organic microcomposite spheres:PMMA/ZnS and PMMA/ZnO micro-nanocomposite spheres with core/shell structure weresuccessfully synthesized by precipitation method using PMMA particles as the coretemplate. PMMA microspheres were pretreated by aqueous ammonia first, and thennanocrystals of ZnS are induced to grow orderly on the surface of PMMA particles. Theeffects of different reaction conditions on the structure and morphology of the synthesizedparticles were characterized. Fluorescence analysis showed that ZnS and ZnO coatedPMMA microspheres has fluorescence light emitting characteristics. ZnS and ZnO crystalon the surface were modified with Mn-doped, the results showed that the fluorescenceemission peaks of Mn-doped PMMA-ZnS and PMMA-ZnO microspheres were shifted tolonger wavelengths, Mn-doped has impact on band gap and ion vacancy of ZnS and ZnO.This thesis enriches forms of functional PMMA microspheres and has broadened theway of studies on functional microspheres. Different types of functional PMMAmicrospheres with special properties were obtained by saponification reaction, copolymer,deposition method, and so on. It will provide important technical support to the newfunctional microspheres applied in medicine, biotechnology, optoelectronics, environmentand other fields.