Synthesis And Characterization Of Polymer-Modified Graphene

In the present dissertation, polymer-functionalized graphene has been summarized based on the recent research progress. Three kinds of graphene-based composites functionalzied by hyperbranched poly(urea-urethane)(HPU), poly(ethylene glycol)(PEG) and perylene-containing polyimide (PPI) have been successfully fabricated by three optimal methodologies, and their chemical strucures and morphologies have been investigated.HPU-grafted graphene have been synthesized by a one-pot polycondensation of tolylene2,4-diisocyanate and diethanolamine in the presence of graphene produced by chemical reduction of graphene oxide (GO). FTIR, TGA and TEM reveal that HPU trees were covalently grafted onto the graphene surfaces with a high amount of up to62%in weight. The resulting functionalized graphene nanosheets were found to be well soluble in polar solvents such as dimethylformamide.PEG-based macroinitiators have been successfully synthesized by a condensation reaction of PEG and an azo-initiator of4,4’-azobis(4-cyanovaleric acid), and their chemical strucute were examined by FTIR and1H NMR. PEG-grafted graphene sheets have been then achieved by solvothermal-reduction of GO nanosheets in N-methyl-2-pyrrolidone (NMP) in the presence and PEG-based macroinitiators that were decomposed to form macromolecular free radicals.A perylene-containing polyimide (PPI) has been successfully synthesized by thermal polycondensation of2,2’-(ethylenedioxy)-diethylamine and perylene-3,4,9,10-tetracarboxylic acid dianhydride in NMP at high temperature. The as-prepared graphite oxide was ultrasonically exfoliated followed by solvothermal-reduction in NMP in the presence of PPI. yielding PPI-functionalized graphene nanosheets. It was found that PPI macromolecules were self-assembled onto the conjugated basal plane of graphene by π-π stacking to form different nanostructures depending on the feed ratio of PPI to GO. This work provides an alternative method to fabricate the multifunctional nanohybrids containing graphene. The present work may open a new route for the fabrication of multifunctional polymer composites containing graphene nanosheets.