【作者】 严成；

【导师】 吴琪琳；

【作者基本信息】 东华大学 ， 材料加工工程， 2010， 硕士

【摘要】 课题研究成功制备了一种具有较高强度的粘胶基活性碳纤维。具体研究了以下内容:（1）制备了具有一定强度的大孔活性碳纤维。首先,分别采用粘胶基预氧化丝和粘胶基碳纤维为原料,经浓度为0.1mol/L的NaCl和H₃PO₄混合溶液浸渍预处理后,分别在700℃、800℃、900℃以及1000℃采用物理-化学活化法,用水蒸气活化制备出了表面富含大孔的活性碳纤维,发现活化温度对粘胶基活性碳纤维成孔及得率、密度、表面截面形貌、比表面积、纤维拉伸强度等性能具有极大的影响,随着活化温度升高,得率、密度及拉伸强度呈下降趋势,而纤维表面大孔数量、比表面积及含氧基团比例则逐渐升高。其中在900℃活化所得的活性碳纤维,表面大孔分布、比表面积、孔径分布以及强度等综合性能优于其他温度段制备出的样品。并且,采用粘胶基碳纤维制备出的活性碳纤维强度要高于粘胶基预氧化丝活化所得的样品。同时我们还探讨了不同盐溶液对孔成形的影响。发现经浓度为0.1mol/L的NaH₂PO₄溶液浸渍预处理后所制备出的活性碳纤维表面大孔的形状及大小分布较均匀,纤维表面大孔沿纤维的径向排列,而且其比表面积比经Na₂HPO₄或Na₃PO₄处理获得的活性碳纤维高,但强度要比后两者略低。（2）探讨了活性碳纤维表面大孔产生的机理。通过FTIR、XPS、TGA、XRD、SEM等多种分析手段,我们发现加入的浸渍预处理剂发挥了类似催化剂作用,即引入催化活性点,并增加了其结构的不均匀性。浸渍预处理剂也增加了活化中心数目,而活化中心正是碳纤维和气化剂反应时的场所。因此浸渍预处理是表面大孔出现的关键。此外,活性碳纤维表面大孔的出现还受温度及其原料结构等因素控制。（3）建立了活性碳纤维孔结构的模型。根据活性碳纤维表面及截面形貌图,发现活化过程是沿纤维径向由表及里进行的,由此提出了一种新型活性碳纤维的结构模型,即表面活性碳纤维-芯部碳纤维的结构。本研究工作在推进表面型大孔活性碳纤维的研究、指导大孔型活性碳纤维的生产和扩大其应用范围等方面具有一定指导作用。更多还原

【Abstract】 Macroporous rayon-based activated carbon fibers（RACF） with high strength were successfully developed.The details are as follows:（1） Macroporous activated carbon fibers with high strength were developed by employing different materials and pretreatment conditions.Firstly,rayon-based oxidized fiber and rayon-based carbon fibers were respectively pretreated by impregnation mix solution with 0.1mol/L sodium chloride（NaCl） and phosphoric acid（H₃PO₄）.Then,the treated fibers were activated by water vapor at 800,900 and 1000℃respectively.We found that activation temperature impacted on the structure and properties of RACF,e.g. yield,density,surface and cross-section topography,specific surface area and fiber tensile strength.The yield,density and fiber tensile strength have obvious descend trends,whereas the numbers of macropores on fiber sufaces,specific surface area and oxygen-containing groups ratio have ascend trends with the increase of activation temperature.Compared with samples at other activation temperatures,the samples activated at 900℃have best comprehensive properties,in terms of macropore size distribution,specific surface area and strength.Moreover,the strength of activated carbon fiber developed by rayon-based carbon fiber was higher than that by rayon-based oxidized fibers.We also discussed the effects of different impregnation solutions such as NaH₂PO₄,Na₂HPO₄ and Na₃PO₄ on the resulting RACF.We found that RACF treated by NaH₂PO₄ possessed macropores with uniform distribution along the fiber axis.And compared to those RACFs treated by Na₂HPO₄ or Na₃PO₄,RACF treated by NaH₂PO₄ exhibited higher specific surface area,but a little poorer tensile strength.（2） We discussed the mechanism of macropore development on surfaces of RACF by using FTIR, XPS,TGA,XRD and SEM.We found that the introduction of impregnation solutions can introduce catalytically active points and the number of activation centers,thus enhance the structural irregularity. These activation centers can provide places for the reactions between carbon fibers and gasification agents. It can be concluded that the introduction of impregnation solutions is the key for the macropore emergence on RACF.Moreover,both the pore numbers and sizes could be controlled by the concentration of the solutions.In addition,the emergence of macropores on RACF surfaces was affected by other factors such as temperature and the structure of raw materials. （3） We proposed a model for macroporous RACF.According to RACF’s surfacial and cross-sectional topography,activation process develops along the radial of the fibers,namely from the surface to the inside. RACFs produced in this study contain the microstructure of activated carbon fiber in skin and that of carbon fibers in core.更多还原