Study On The Preparation And Performance Of Carbon Functional Materials

Based on the characteristics of light weight,corrosion resistance,excellent dielectric properties,and low cost,carbon materials have been increasingly used in microwave absorbing materials and capacitors.The preparation of carbon-based composite absorbing materials has gradually developed towards the goal of simplicity,low cost,easy preparation,and controllability.As the second largest renewable natural polymer material in nature,lignin has the characteristics of low price,wide sources,and high carbon content.Therefore,lignin can be used as a precursor to prepare carbon materials.Coal is also a cheap resource with high carbon content,but its ash content is high,and the electromagnetic wave absorption performance of the carbonized material is not high.Mixed carbonization of coal and lignin can improve its electromagnetic wave absorption performance.The main research contents of this paper include the preparation and electrochemical performance study of lignin-based graphene,the preparation and electromagnetic wave absorption properties study of lignin-based carbon/polyaniline composites,and the preparation and electromagnetic wave absorption performance study of coal/lignin derived functional materials.The following conclusions are drawn through the above research:(1)Preparation and electrochemical performance study of lignin-based graphene.Stir the mixture of ferric nitrate,tetrahydrofuran and lignin uniformly,heat the water bath to pretreat the lignin precursor,and then calcinate the lignin precursor at a high temperature and perform impurity removal treatment to obtain lignin-based graphene.The samples were characterized by X-ray diffractometer(XRD),Fourier infrared spectrometer(FT-IR),high resolution transmission electron microscope(HRTEM)and Raman spectroscopy(Raman)and other test methods,and their electrochemistry was tested performance.The results show that the high-temperature pyrolysis treatment of lignin can produce graphene nanosheets,which have the characteristics of partial aggregation of layers and partial retention of the layer structure.In addition,the prepared lignin-based graphene has good specific capacitance and electrochemical reversibility and can be used in capacitors.(2)Preparation and electromagnetic wave absorption properties study of lignin-based carbon/polyaniline composites.Polyaniline was synthesized by in-situ polymerization,and the precursor was obtained by adding a certain amount of lignin and different amounts of polyaniline to heating in a water bath to obtain the precursor,which was dried in a drying box and then calcined in a tubular furnace to prepare lignin-based carbon/polyaniline composite material.XRD,Raman,FT-IR,HRTEM,Scanning Electron Microscope(SEM)and Network Vector Analyzer(VNA)were used to study the composition,microscopic morphology and electromagnetic parameters of the composite in detail.The results show that the dielectric properties of the lignin-based carbon/polyaniline composite can be adjusted by designing the material ratio of the composite material,which can achieve reasonable impedance matching and energy attenuation at the same time.The best RL of the lignin-based carbon/polyaniline composite material reaches-50.96 dB at 8.88 GHz,the thickness is 3.09 mm,and the effective absorption bandwidth is 4 GHz.Therefore,the lignin-based carbon/polyaniline composite material is expected to be an electromagnetic wave absorbing material for application.(3)Preparation and electromagnetic wave absorption performance study of coal/lignin derived functional materials.The coal,lignin,potassium hydroxide and an appropriate amount of deionization are mixed and stirred uniformly,dried into a solid and put into a tube furnace for calcination to prepare a coal/lignin derived functional material.The synthesized product was characterized by FT-IR,SEM,and thermogravimetric analyzer(TG),and its electromagnetic wave absorption performance was tested.The results show that the best RL of the coal/lignin derived functional material is-51.89 dB,the corresponding peak intensity frequency is 6.24 GHz,the thickness d=4.14 mm,and the effective absorption bandwidth is 2.64 GHz(from 4.96 GHz to 7.6 GHz),Therefore,coal/lignin derived functional materials exhibit super-strong,wide-band,and light-weight electromagnetic wave absorption properties.Figure[29]table[6]reference[105]...