The Surface Modification Of Garphene Oxide And The Preparation Of Its Composite Material

New materials become the hotspot of international research,and carton materialshas been widespread concern of researchers.In recent decades,it has been a hot topicof the IT industry research and development.Graphene, a monolayer of carbon atomspacked into a dense honeycomb crystal structure, has attracted tremendous attentionfrom both the experimental and theoretical scientific communities since it was foundin2004.Due to the unique nanostructure and extraordinary properties.graphene basedmaterials have shown promising applications in electronics, optics, magnetics,biomedicine,catalysis,sensors,energy storage etc. Although graphene is an idealsubstrate that is suitable for some purposes, it contains rare surface functionalmoieties and very limited dispersibility in solvents, seriously limiting the exertion ofits great potentials. Thus,developing chemical methods to functionalize graphene(graphene oxide)has become one of the most critical issue s in the exploring ofgraphene technologies.Rigid Polyurethane foam(RPUF) is an important polymericfoam material because of its unique properties,such as low mass,excellent heatinsulation,excellent shock absorption,relatively high sPecific compressive strength，the flexibility in properties that can be obtained by varying the synthesis andproeessing conditions,and good cohesiveness with most materials.Because of theseadvantages,RPUF is one of the most widely used Plastics and has been used invarious fields of the national economy.However,RPUF has some disadvantages,suchas relatively low mechanical properties compared to structure materials,be apt toaccumulate charge,easy to be burned and cause fire accident and so on.Oranically,weadded the surface modification of the GO into the rigid polyurethane material toimprove its thermal stability.This the main contents of my paper:Firstly, because the improved Hummers method has many advantages,such as therelatively simple of the reaction process,relatively short reaction time,highsecurity,low price of the reaction raw materials,environmental pollution and so on. weproduced the graphene oxide by improved Hummers,and the product were characterized by a variety of spectra and morphology. The improved Hummers in theprocess of preparation of GO is divided into three stages:low-temperature,mediumtemperature,high-temperature.A lot of papers have reported that affected the GOdegree of oxidation of the factors in the preparation process.Based on literaturereports and preliminary work, We researched and discussed the influence ofhigh-temperature of the oxidation time on the degree of oxidation of the grapheneoxide in the preparation of graphene oxide. We token the products by elementalanalysis and Raman spectrum etc,the test results showed the impact of oxidation timeon the degree of oxidation of the graphene oxide.The TGA result showed the degreeof oxidation on the thermal stability of the graphene oxide.Finally,we used TDI to be modified the GO, we think TDI successfully graftedon to the GO by IR spectra analysis.Then we used TDI to be modified the differentoxygen content of GO and token the samples by elemental analysis,the results showedthat the nitrogen content in the GO changed with the oxygen content of GO,with theincrease in the oxygen content in the GO,the nitrogen content in the GO-TDI werecorresponding increase.We added the GO into the polyurethane composite material inthe first time,the SEM images showed that the graphene oxide dispersion in thepolyurethane material was poor,and TGA measurements showed that with the increaseof the graphene oxide addition,the thermal stability of the grapheneoxide/polyurethane composite had not improved.Because the graphene oxidedispersion in the polyurethane foam was relatively poor,we usedtoluene-2,4-diisocyanate which contained two isocyanate groups for the surfacemodification of graphene oxide.One remarkable result after modification was that theobtained graphene oxide was dispered stably in organic solution.SEM images showedthat the modified graphene oxide dispersion in the polyurethane foam markedlyimproved.TGA tests showed that with the increase of the modified graphene oxideaddition, the thermal stability of modified graphene oxide/polyurethane compositehad significantly improved.We compared the thermal stability of the grapheneoxide/polyurethane composite and modified graphene oxide/polyurethanecomposite,results showed that the thermal stability of modified graphene oxide/polyurethane composite was better than the graphene oxide/polyurethanecomposite.