Preparation And Characterization Of Magnetic Polymers Based On Pyrene And POSS

The magnetic poly(ionic liquid)s have the physical and chemical properties of the ionic liquids and processability,thermal stability and tolerance of the polymers,and can also be used as magnetic functional polymer materials because of their magnetic response in an external magnetic field.Magnetic poly(ionic liquid)s have important applications in magnetic separation,adsorption,catalyst and absorbing materials.However,magnetic poly(ionic liquid)s are mostly paramagnetic at room temperature and magnetic properties are weak,which limits their application fields.Therefore,the study of the magnetic properties of magnetic poly(ionic liquid)s is of great significance for the expansion of their applications.In this thesis,the magnetic monomer based on pyrene was designed and synthesized,and magnetic polymer was obtained via ring-opening metathesis polymerization(ROMP)and related reactions.The structure of magnetic monomer and polymer was verified by nuclear magnetic resonance spectroscopy and Raman spectroscopy.The magnetic properties of magnetic monomer and polymer were investigated by a superconducting quantum interferometer(SQUID)method.The results showed that the monomer and polymer exhibit superparamagnetism at room temperature due to the introduction of?-?stacking,and the magnetic properties are changed greatly.In addition,due to the introduction of pyrene groups,Fe³⁺in solution can be detected by fluorescence emission spectroscopy with monomers and polymers,and the minimum detection limit for Fe³⁺is 10^-7 M.At the same time,a reversible addition-fragmentation chain transfer(RAFT)reagent containing POSS was synthesized.Tadpole-shaped magnetic polymers for different molecular weights were synthesized by RAFT polymerization with 4-vinylpyridine as monomer.The polymers were verified by NMR and Raman spectroscopy,and molecular weight and its distribution was measured by gel permeation chromatography(GPC).Magnetic properties of magnetic polymers were studied by SQUID method and the results showed that the polymers were paramagnetic.When the magnetic polymers were self-assembled in solution and thin film,the magnetic susceptibility for the polymer with degree of polymerization of 11 increased.As the degree of polymerization increased,the magnetic susceptibility increased less even decreased.