Preparation And Characterization Of Biocarbon-reinforced Composite

Composite material is a complex solid material composed of two or more materials.Compared with raw materials,composite materials have obvious advantages in specific strength,fatigue resistance,processing technology and designability.At present,the research on composite materials is mostly use inorganic fillers.Graphitized biocarbon has the inherent skeleton structure,which can provide support for the preparation of composite materials.And the rich functional groups in the graphite layer can be effectively merged with the high molecular polymer to effectively improve the performance of the material.In this thesis,biocarbon with graphitization structure was prepared from bamboo and Radiata pine by high temperature pyrolysis.The structure and functional groups of biocarbon were determined by a series of characterization methods such as Raman spectroscopy,XRD,SEM and FT-IR.Furthermore,the optimum pyrolysis process was evaluated by factors,such as holding time and pyrolysis temperature.And the biocarbon prepared by the best pyrolysis process was used to fabricate biocarbon/PE composite.It indicated that the biocarbon had a certain graphitization.The biocarbon also retained the porous structure of biomass,and its structure was similar to its original form prior to the pyrolysis.It also showed the biocarbon can effectively enhance the physical properties of composite materials.This thesis is mainly divided into three parts:?1?Bamboo-based and Radiata pine-based biocarbon were prepared under N₂ and air atmosphere at 1300?.Due to its higher lignin content,the biocarbon yield of Radiata pine?27.4%,under N₂?is higher than that of bamboo?22.0%,under N₂?.Compared with air atmosphere,the biocarbon yield under N₂ atmosphere is slightly higher by 4.2-7.3%.The analysis of Raman spectroscopy,X-ray diffraction?XRD?and Fourier-transform Infrared?FT-IR?spectroscopy on the biocarbon revealed the graphite structure in the biocarbon.The graphitization was higher in Radiata pine-based biocarbon than in the bamboo-based biocarbon.The SEM analysis on the biocarbon showed the biomass porous structure remained unchanged during pyrolysis.Under air atmosphere,some white metal oxides were generated on the biocarbon surface,which affected the surface smoothness.Different structural characteristics in the biocarbon would render them different applications.?2?Biocarbon was prepared from Phyllostachys pubescens Dendrocalamus edulis,Dendrocalamus latiflorus and Radiata pine by pyrolysis under N₂ atmosphere at temperatures of 900?,1100?and1300?,with heating rates of 120?/h,200?/h and 280?/h,and holding times of 1 h,2 h and 3 h.The effect of pyrolysis condition on the bicarbon was evaluated by Raman spectroscopy and X-ray diffraction?XRD?to obtain the optimum pyrolysis process.It suggested that the quality of biocarbon was significantly affected by the pyrolysis temperature and heating rate.The quality of biocarbon may decrease with the increase of holding time.To obtain biocarbon with high quality,the pyrolysis temperature and heating rate could be controlled at 1300?and280?/h,respectively,and the pyrolysis time was set to 2 h.?3?The biocarbon was prepared from Phyllostachys pubescens Dendrocalamus edulis,Dendrocalamus latiflorus and Radiata pine at the optimum pyrolysis process,which the temperature,heating rate and pyrolysis time was at 1300?,280?/h and 2h,respectively.The composites were prepared by adding 10%and 30%of the biocarbon into PE,respectively.With the adding of 30%Dendrocalamus latiflorus-based biocarbon in PE,the SEM,dynamic thermomechanical analysis?DMA?and universal testing machine analysis showed that the tensile strength and tensile modulus of composites were increased by 61%and261%,respectively,and the elongation at break was reduced by 89.0%.Meanwhile,the decrease of the storage modulus of composites was effectively slowed down by adding the 30%Radiata pine-based biocarbon.Compared to pure PE,the storage modulus of 30%Radiata pine-carbon composites increased from 8.4%at-100?to 81.7%at 50?,and the thermal stability of composites was improved obviously.The loss factor was improved.The biocarbon reinforced composite showed slower viscosity rising rates compared with pure PE,Composite materials slow down the rising rate of the viscosity of composite materials,indicating the potential application of biocarbon in high temperature resistant materials.At the same time,the addition of biochar has a certain degree of thermal stability to the composite materials.The scanning electron microscopy?SEM?analysis demonstrated that biocarbon can improve the fluidity of polymers and enhance physical strength,which provided guidance for further development of high-strength composites.