Preparation And Characterization Of Graphene-based Composites

Nowadays,more and more electronic products have brought electromagnetic radiation,which is harmful to both human beings and the environment.Under this circumstance,more kinds of electromagnetic microwave（EM）absorbing marterials are in urgent need to protect ourselves from the electromagnetic pollution.However,the traditional EM absorbing materials can’t meet the developing demand for EM absorbing materials as their narrow EM absorbing band and low EM absorptivity.Therefore,reseachers around the world pay great attention to the research of new kinds of EM absorbing materials.Graphene exhibit good mechanical,thermal,and electrical performance,providing wide applications in many fields.The research of graphene-based macro-forms has accelerated the application of graphene in daily life.The graphene-based macro-forms are three-dimensions networks built from graphene.They keep the great properties of graphene from microcosm.At the same time,they exhibit as porous materials at the macroscopic level.In this paper,reduction and self-assemble method was picked up from four kinds of methods as the products of this method exhibited best formability and compressibility.In this method,graphene sponge was prepared from graphite oxide.Ethanediamine（EDA）was chosen as cross linker as well as reductant.Moreover,freeze-drying method was used to get a well three-dimensional structure graphene sponge.The FITR and XPS spectrums show that graphite oxide was reduced during the preparation of graphene sponge.In addition,the SEM graph show that the graphene layer in graphene sponge is pretty large.Finally,the graphene sponge show well reflection loss between 1-18 GHz and 18-26 GHz,and the maximum reflection loss of graphene can reach-15 dB.In this paper,polyaniline（PANI）/graphene sponge was made from graphite oxide and aniline using a “in situ polymerization-reduction self-assemble” method.EDA was chosen as the reductant and cross linker in this method.The XPS and FTIR result showed that there were C — N 、 R — C=NH 、 C — NH — C and nitrogen-containing heterocycle in PANI/graphene sponge.Besides,the product showed EM absorbing property between 1-18GHz、18-26 GHz and 26-40 GHz.A new polyaniline（PANI）/ ferroferric oxide（Fe₃O₄）/graphene sponge was prepared by “in situ polymerization-reduction self-assemble” method in Chapter Four of this paper.The PANI/Fe₃O₄/graphene sponge was made from a kind of highly water-dispersible Fe₃O₄,aniline,and graphite oxide.EDA was chosen as the reductant and cross linker in this method.The FTIR spectrum of PANI/Fe₃O₄/graphene sponge exhibited a band around 617 cm-1,which attributes to the Fe — O stretching.In the XPS spectrum of PANI/Fe₃O₄/graphene sponge,we can see the characteristic peak of Fe₃O₄ and Fe（3）acethylacetonate at 710.9eV and 711.8eV.Moreover,the product showed weak EM absorbing property between 1-18GHz、18-26 GHz and 26-40 GHz.