Synthesis And Property Study Of Polyelectrolyte Based On Polyethyleneimine

Polyelectrolyte,as a very important functional material,has attracted tremendous attention due to the property derived from polymer and capability of carrying cation and anion.Among all the polyelectrolytes,Polyethyleneimine(PEI),known as the polymer with the most abundant amino groups,has attracted abundant attention from researchers due to its feature of easy to cationization,highest cationic-charge-density potential and easy to functionalization.In this thesis,PEI based magnetic polymers(MPEI)with different molecular weight and linear and chain structure were prepared via quaternization,ion exchange and FeCl3 complexation process.MPEI with different Fe content was obtained by alternating quaternization time.The MPEI displayed paramagnetic property and could move under the attraction of external magnetic field initiated by a neodymium magnet.The magnetic susceptibility of MPEI increased linearly with Fe content.This discovery,to some extent,offered theoretical and experimental foundation for PEI based magnetic polymer design and synthesis.Magnetic nano particles was obtained via further pyrolysis of MPEI.The pyrolysis product of MPEI was well shaped as nano particles with diameters ranging from 2nm to 10 nm and was highly crystalline with crystalline phase mainly composed of cubic crystalline Fe3O4 and FeN.What's more,the resultant nano particles displayed soft ferromagnetic property which was hopeful to be applied to hyperthermia and directed drug release.Besides,Functional polyelectrolyte QPEI-OH based on branched PEI carrying OH-anion was prepared via quaternization and ion exchange process.The prepared QPEI-OH was able to catalyze the nucleophilic substitution reaction between Benzyl alcohol and benzyl bromide and the catalytic efficiency was near 100%.