Technical Research On The Preparation Of Carbon Material From Cellulose By Carbonization At High Temperature

Carbon microspheres (CMBs), Carbon nanotubes (CNTs) and othercommon carbon materials, which exhibited excellent mechanical, thermal,electrical, etc performance,have been widely researched by scientists indifferent field.As a result,these materials represent tremendous value inscientific experiments and production practices field.Considering the ChemicalVapor Deposition (CVD) has a simple,environmentally process and hassingle products, the reaction also can be carried out continuously,so CVDmethod is regarded as a good approach to synthesis carbon materials. Currently,most of the raw materials for the preparation of carbon materials arehydrocarbons, deoiled asphalt, coal tar and other non-renewable resources.China is facing a serious challenge from environment and resources,looking for clean and renewable resources are becoming an inevitable trend.Meanwhile,cellulose are rich in carbon elements,being with its big advantage-wide rangeand abundant storage,it can be the ideal raw material for the preparation ofcarbon.In this research,different cellulose were used as carbon sources andcarbon materials with different morphologies were prepared by variousprocesses. in first part, Microcrystalline cellulose-the simplest cellulose wasused as raw materials to prepare carbon materials by CVD merthod,and theinfluence of the ferrncene content,flow rate,reaction time on materialmicrostructure, the crystalline structure and functional groups were researchedthrough single factor experiment.Optimal conditions for preparing carbonnanotubes were confirmed and even provided an experimental basis for theidea of preparing carbon materials from cellulose.Other resources were usedalong,such as natural fibers-cotton fibers and widely used fibers-regeneratedcellulose fibers, in this part,fibrous carbon materials were obtained bycarbonization after immersion preparation and pre-oxidation treatment,and theyield is high.The main results of research are as follows:(1)Using cellulose as carbon source and ferrocene as catalyst,carbonmaterials were synthesised by chemical vapor Deposition by controlling theflow rate, catalyst content, reaction time.The best process of preparationcarbon nanotubes were finded-when catalyst content is30%, react at900℃, the gas rate is0.15L/min. When react at900℃for2minutes, bent CNTs canbe synthesized,and when react at900℃for30minutes, straight CNTs can besynthesised.(2) Using cotton fibers as carbon source,carbonization after immersing byKH550and ammonium chloride solution separately, the products with less curlshape than cotton fibers can be obtained,.After immersing preparation,theyield of products were improved,even achieved28.3%when oxidization for60min.(3)The yield of products from regenerated cellulose fibers were significantlyimproved after immersion treatment, from10.9%to27.5%-33.7%.(4)Small holes can be observed on the etched surface of products fromunsteeped regenerated cellulose fibers.While the serrated cross-section andsignificant longitudinal grooves can be observed on the surface of productsfrom steeped regenerated cellulose fibers.In conclusion,immersionpretreatment of regenerated cellulose fibers is in the benefit of morphologyprotection of products.