【作者】 赵鑫；

【导师】 刘守新； 李斌；

【作者基本信息】 东北林业大学 ， 高分子化学与物理， 2013， 硕士

【摘要】 赋予多孔炭材料以特定的形貌及孔径结构,无论是从材料合成科学的角度,还是从材料应用的角度,均具有重要的意义。生物质原料的主要成分是纤维素、半纤维素和木质素,结构上含有较多的氧,在热解时不经过液相这一步,炭化时是典型的固相炭化,微晶的择优取向困难,难于生成高度有序的孔结构。以生物质为基体,采用常规的惰性气氛下炭化活化,其生物遗态的结构将在很大程度上保留。因此,传统方法在制备具有指定形貌及孔径结构生物质基多孔炭方面存在巨大障碍。本文以酚醛树脂为原料,经过树脂化、自身组装聚合、活化、炭化等工艺制备山具有球形形貌的微-介双阶多孔炭材料；以此为基础,选用落叶松木屑为原料,经木材液化、热固树脂化、高温炭化过程,选用三嵌段聚合物F127制备落叶松基介孔炭材料,并通过调整反应条件控制炭材料的表面形貌,制备出具有球形结构的介孔炭材料；通过KOH活化法制备出球形微-介双阶多孔炭；通过控制反应条件调整反应物粘度,制备出具有有序的孔隙结构无支撑体分子筛炭膜。通过X-射线衍射分析、热重分析、扫描电子显微镜、透射电子显微镜、低温氮气吸附仪对制备材料进行了性能及应用研究。论文主要内容如下：以苯酚和甲醛为原料,在碱性条件下聚合,然后在酸性条件下与软模板剂嵌段共聚物F127自组装形成中间相,经高温煅烧合成球形微--介双阶多孔炭(HCSp)。结果表明,pH值、软模板剂用量和活化温度对样品形貌有调控作用,软模板剂F127的理想质量分数为18.6%,pH值为0.5,活化温度为700℃。此时可制备出直径为100-200nm的球形炭,球形粒子分散均匀,排列规整,呈明显蠕虫状排列的孔隙结构,比表面积为503m2/g,孔容积0.416cm3/g,介孔孔径集中分布在2.9nm,微孔主要分布在1.3nm间。随着活化温度升高,炭球的比表面积和孔容积增大,平均孔径减小。以落叶松木屑为原料,经苯酚液化形成液化产物,与甲醛反应形成落叶松基酚醛树脂,选用嵌段共聚物F127作为软模板,与酚醛树脂进行自组装反应形成球形结构,经水热法优化球形结构,最后经高温煅烧去除软模板剂得到球形介孔炭材料(CS1),通过控制F127的浓度控制炭材料的形貌和尺寸,炭化温度调整孔形伏。结果表明,F127浓度为6%时制备的炭具有较好的球形结构,随着F127量的增加,形貌尺寸减小,由球形形貌转化为树莓状形貌。随着炭化温度的增加孔结构由螺旋状转化为蠕虫状再转化为波纹状,同时,700℃反应条件下的样品比表面积、孔容和微孔含量分别增加至410m2/g,0.291cm3/g,48.5%。然而孔尺寸呈明显下降趋势。以落叶松木屑为原料,F127为软模板剂,通过木材液化,树脂化和活化法制备微-介双阶多孔炭球(HCS1),炭球尺寸主要集中在20-30μm,介孔集中在2.0-4.3nm,微孔主要集中在1.2-2.0nm。在700℃下具有最高的比表面积和孔容积,分别为1064m2/g和0.503cm3/g。炭材料的孔径结构通过不同温度活化控制,活化温度越高,微孔也随之增加。当活化温度达到700℃时,比表面积达到1064m2/g,孔容达到0.503cm3/g。此外,比表面积和总孔容随着活化温度的增加而增加。HCSl在形成过程中发生了四步分解过程,分别在250,375,450和650℃,250℃的失重峰对应了F127的分解,375℃的峰对应树脂的初级碳化形成碳基材料,450℃的峰对应二级碳化过程,形成炭材料,650℃的峰对应的是K2CO3的分解过程。以落叶松苯酚液化物为原料,利用浸渍法铺成非支撑体膜,调整反应时间和温度控制反应物粘度,通过高温炭化制备具有有序的孔隙结构的分子筛炭膜(MSCM),700℃煅烧条件下膜厚度为400μm,孔结构主要集中在1-3nm,随着炭化温度的增加,介孔更加集中有序。比表面积逐渐增加,从367m2/g增加469m2/g;孔容也从0.198cm3/g增加到0.250cm3/g,这主要是因为微孔含量的增加,微孔百分比从80%增加到87%,表明分子筛炭膜具有较多的微孔结构,微孔含量的增多导致平均孔径从2.15nm减小到2.13nm。更多还原

【Abstract】 Porous carbon materials with specific morphology and pore size have the vital significance on the perspective of synthetic materials science and the perspective of material application. Biomass raw materials mainly include cellulose, hemicellulose and lignin, contain more oxygen on structure. It is typical of solid-phase carbonization without going through liquid phase during pyro lysis in this step; microcrystalline preferred orientation is difficult, obtained highly ordered pore structure is difficult also. Using biomass as matrix, carbonization and activation by the conventional style under inert atmosphere, its biological ceramic-wood structure will be largely preserved. As a result, preparation of specified shape and aperture structure of biomass carbon by the traditional method has a big obstacle.This paper aimed to preparing spherical carbons with hierarchical micro-mesoporous structures from the resinification, self-assembly activation and carbonization from phenolic resin as source. Based on the preliminary exploration, spherical mesoporous carbon was prepared using larch sawdustas the starting material, which is cheap and renewable, F127as soft-templed by liquefaction, resinification, self-assembly polymerization, activation, carbonization technology. After chemical activation, micro-mesoporous carbon spheres were obtained. In view of the carbon materials with good pore structure, the molecular sieve carbon memebrane was preparated without supporting through controlling the reaction condition adjustment reactant viscosity. The obtained porous carbon materials were characterized by X-ray diffraction (XRD), scanning electron spectroscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption-desorption isotherms, and thermogravimetric analysis (TGA).In this paper, bionass energy, wood liquefaction, mesoporous carbon, micro-mesoporous carbon and molecular sieve carbon membranes were reviewed. Furthermore, the topic research background, methods, contents and innovation points and the main research methods were introduced.A facile soft-template method was developed for the synthesis of spherical micro-mesoporous hierarchical carbon material (HCSp) by using phenol and formaldehyde as carbon and Pluronic F127as templat. Results showed that morphology of caron can be regulated by the dosage of soft-template, pH and activation temperature. The optimum condition was determined as mass fraction of F12720%, pH0.5and activation temperature700℃. The prepared porous carbon exhibited spherical morphology with uniformly diameter of100-200nm. Vermicular pore structure, together with bimodal pore size distribution peak2.9nm and1.3nm was observed. Maximum of surface area and pore volume can reach503.20m2/g and 0.42cm3/g, respectively. Results revealed that surface area, pore total volume of carbon spheres increased with the increasing of activation temperature. However, pore size showed reverse trendency.Mesoporous carbon spheres (CS1) with tunable morphology and pore structure were prepared from liquefied larch sawdust via coupling soft-templated and the hydrothermal method. The morphology and size of carbon spheres can by controlled by the concentration of F127; the pore structure can be tunable by carbonization temperature. The results showed that perfect carbon sphere can be achieved when the concentration of F127was6%. The morphology of carbons was from spherical-shaped to raspberry-like, and particle size decreased with increasing F127concentration. Pore structure transformed from spiral-like, vermicular-like to wave-like with the increasing of the carbonization temperature, meanwhile, the surface area, pores volume and microporous content were increased to410m2/g,0.291cm3/g and48.5%respectively when carbonization increased to700℃. However, pore size showed reverse trendency.Spherical carbons with hierarchical micro-mesoporous structures (HCS1) were prepared from the liquefaction, resinification and activation of larch sawdust. Block copolymer F127reacts with liquefied larch to form carbon spheres. Carbon spheres with diameters20-30μm, together with vermicular porous structures consisting of2.0-4.3nm mesopores and1.2-2.0nm micropores were formed. The maximum surface area and pore volume were1064m2/g and0.503cm3/g, respectively, at an activation temperature of700℃. The carbon pore size was controlled by KOH at different activation temperatures. At high temperatures, the mesopores and micropores in the material increased. When the activation temperature increased to700℃, the maximum surface area and pore volume reached1064m2/g and0.503cm3/g, respectively. In addition, the surface area and the SHC pore total volume increased with increasing activation temperature. The mesophase of SHC decomposed rapidly in four stages, at250,375,450and650℃, corresponding to the decomposition of F127, primary carbonized products, secondary carbonized products and K2CO3, respectively.Based on the result of the preparation of mesoporous carbon spheres from larch-sawdust, molecule sieves carbon membrane (MSCM) with thickness of400μm and pore size centrated at1-3nm was preparated by adjusting reaction time and temperature to control viscosity of liquefied larch. The surface area increased from367m2/g to469m2/g, pores volume increased from0.198cm3/g to0.250cm3/g, because of microporous content increased from80%to87%. It indicated that molecule sieves carbon membrane had more microporous, resulted average pore size decreased from2.15nm to2.13nm.更多还原