Study On Poly(γ-benzyl-L-glutamate) Modification Of Graphene Oxide And Graphene Oxide Modification Of Inorganic Nanoparticles

Carbon has a unique bonding ability, which can form a wide variety ofcompounds and various allotropes. Carbon materials have unique performance andhuge potential application in different fields. It attracted a lot of research enthusiasm.Compared with fullerenes and carbon nanotubes, graphene becomes a popular carbonmaterial in recent years. It has many unique properties, such as high electron mobility,good thermal performance, high mechanical strength, electrochemical and opticalproperties, etc. In recent years, a lot of researchs were focused on the modificationand application of graphene. Modification of graphene can optimize its properties,achieve the ideal requirements and expand its application. In this background, fourmain researches have been carried out.Firstly, base on the method of graphene modification, covalent modification,which is forming stable covalent bonds between polymers or other small moleculesand the surface of graphene is one of the important methods. In this thesis, we usedthe poly glutamic acid benzyl ester ring opening polymerization covalent modifiedthe graphene oxide, which can improve the dispersion of graphene oxide in theorganic phase. Poly glutamic acid benzyl ester is a kind of synthetic peptides, whichhas important applications in drug release, drug delivery, tissue engineering, medicineand other fields. It is a kind of non-toxic and environmentally friendly polymermaterials. The poly glutamic acid benzyl ester chains act the role of improving itshydrophobicity. At the same time it provides the space steric hindrance, preventsaggregation between layers. Dispersibility in organic solution was obviouslyimproved.Secondly, graphene oxide-poly glutamic acid was prepared by deprotection.ferroferric oxide and zinc oxide nanoparticles were loaded on the grapheneoxide-poly glutamic acid by the method of in-situ growth. The composite material hasphotocatalytic activity and can be recycled by magnetic separation. The GO and polyglutamic acid have played an important role in a template. The obtained nanoparticleshave a good dispersion on graphene oxide surface. GO can also promote photoproduction exciton separation and absorb the organic molecules of pollutantsThirdly, Poly glutamic acid benzyl ester-graphene oxide can act as an interfacelayer on the nano silica surface. Graphene oxide and positively charged aminationnano silica microspheres have a self-assembly in solution to form the coatingstructure. It was proved by image of SEM and TEM that after the modification ofnanoparticle, the graphene was successfully coated on the surface of nano silicamicrospheres. And microspheres were crosslinked with each other by graphene oxide.It formed a special morphology. The obtained modified nanoparticles were dispersedinto polylactic acid matrix to improve its properties. It is proved by section SEMimage analysis of poly (glutamic acid benzyl ester)-graphene oxide-silica/polylactic acid materials that silica particles exhibited effective dispersion inpolylactic acid. Mechanical properties of poly (lactic acid) were improved. Tensilestrength and young’s modulus have increased significantly. After added nanoparticlemass fraction in5wt%, the tensile strength of poly (lactic acid) increased by39%and Young’s modulus by42%respectively. And thermal stability have a slightlyincrease at the same time. After asymmetricly modified by poly glutamic acid benzylester, graphene oxide can effectively act as the interface layer, which increased theinterface bonding. It can help transfer and disperse stress between the interfaces. Thusthe nanoparticles improved the mechanical properties of nanocomposite.