微波—双氧水联合处理炭纤维的工艺及性能研究

发布时间：2018-04-22 03:28

本文选题：炭纤维 + 微波诱导氧化　；参考：《湖南大学》2015年硕士论文

【摘要】：炭纤维是具有优异性能的工程材料,常作为各种复合材料的增强体,炭纤维增强复合材料由于良好的机械性能是先进复合材料应用的首选。炭纤维与基体的界面粘结是控制复合材料整体性能的关键,但是由于炭纤维表面惰性等因素的影响,其与复合材料界面的粘结较弱。因此,改性炭纤维表面的研究是必需的。本文研究了炭纤维的表面改性、表征以及微滴包埋拉出法测界面剪切强度。采用一种新的方法—微波辐射双氧水氧化法,对炭纤维进行表面改性,通过使用场发射扫描电子显微镜(FE-SEM)、X射线光电子能谱仪(XPS)、拉曼光谱仪(Raman)和激光显微仪等表征手段分析炭纤维表面物理化学性质;并用微滴包埋拉出法测试复合材料的界面剪切强度,并总结分析了影响界面剪切强度的一些因素。借助FE-SEM、XPS、Raman和激光显微仪等手段探索各种工艺参数(微波功率、处理时间、双氧水浓度等)对炭纤维表面性质的影响。通过观察分析扫描电镜图像发现,纤维表面形貌随着处理条件的改变出现不同的变化,改性后纤维表面出现凹槽和孔洞,还出现一些纳米尺寸的突起和白斑等特殊结构;通过XPS分析表明,处理后纤维表面含氧量和含氮量都在增加,处理条件的改变和炭纤维种类的不同增加的含量也不同,实验室自制的一种沥青基炭纤维改性后氧含量增加最多,达到16.29 mol%,主要是C-O、C=O等含氧官能团的增加。Raman光谱发现R值(D峰和G峰的面积比)增加,表明微波诱导氧化处理增大了炭纤维表面结构的无序化。激光显微仪测定纤维表面的粗糙度,展示了粗糙度值的增加。同时本文研究了五种类型的炭纤维,其表面形貌和表面元素发生了变化,表明这种方法潜在的广泛适用性。用微滴包埋拉出法测试炭纤维与环氧树脂的界面剪切强度(IFSS),来评价炭纤维与环氧树脂基体的粘结情况。从负载-位移曲线读取树脂小球从炭纤维上脱落时的脱粘力值,并利用扫描电子显微镜观察了脱粘树脂小球和炭纤维的状态,然后定量的计算出两种样品的IFSS平均值以及其标准方差、离散系数,并讨论了IFSS同树脂小球的长度与直径、纤维直径的关系。研究发现:所测量的界面剪切强度值与环氧树脂小球的长径比近乎成正比,与纤维直径成反比,与环氧树脂小球的长度和纤维直径的比值反比,与环氧树脂小球的直径和纤维直径的比值成反比。
[Abstract]:Carbon fiber is an engineering material with excellent properties, which is often used as a reinforcement of various composites. Carbon fiber reinforced composites are the first choice for advanced composite applications due to their good mechanical properties. The interfacial bond between carbon fiber and matrix is the key to control the overall properties of composites, but the bond between carbon fiber and composite interface is weak due to the influence of inert carbon fiber surface. Therefore, it is necessary to study the surface of modified carbon fiber. In this paper, the surface modification, characterization and interfacial shear strength of carbon fiber were studied. The surface of carbon fiber was modified by microwave irradiation hydrogen peroxide oxidation method. The physical and chemical properties of carbon fiber surface were analyzed by means of field emission scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), Raman spectrometer (Raman spectrometer) and laser microscopy. The interfacial shear strength of the composites was measured by microdrop embedding and pulling method, and some factors affecting the interfacial shear strength were summarized and analyzed. The effects of various technological parameters (microwave power, treatment time, concentration of hydrogen peroxide, etc.) on the surface properties of carbon fibers were investigated by means of FE-SEMX Raman and laser micrometer. By observing and analyzing the SEM images, it was found that the surface morphology of the fibers varied with the change of the treatment conditions. After the modification, there were grooves and voids on the surface of the fibers, and some special structures such as nano-sized protuberances and white spots were also found. XPS analysis showed that the oxygen content and nitrogen content on the surface of the treated fibers were increasing, the changes of treatment conditions and the content of carbon fibers were also different, and the oxygen content of the modified asphalten-based carbon fiber made by the laboratory increased the most. The increase of oxygen functional groups, such as C-O, Con O, and so on. Raman spectra show that the ratio of R value D peak to G peak increases, which indicates that microwave induced oxidation treatment increases the disorder of carbon fiber surface structure. The surface roughness of the fiber was measured by laser microscopy, and the increase of the roughness value was shown. At the same time, five types of carbon fibers have been studied, their surface morphology and surface elements have been changed, which indicates that this method is widely applicable. The interfacial shear strength of carbon fiber and epoxy resin was measured by micro-drop embedding pull method to evaluate the bond between carbon fiber and epoxy resin matrix. From the load-displacement curve, the value of the desorption force of the resin ball was read when it came off from the carbon fiber, and the state of the resin ball and the carbon fiber was observed by scanning electron microscope. Then the average value of IFSS and the standard variance and dispersion coefficient of the two samples were calculated quantitatively. The relationship between the length of IFSS and the diameter of the resin pellet and the diameter of fiber was discussed. It is found that the measured interfacial shear strength is in direct proportion to the ratio of length to diameter of epoxy resin ball, inversely proportional to fiber diameter, and inversely proportional to the ratio of the length of epoxy resin ball to fiber diameter. It is inversely proportional to the ratio of the diameter of the epoxy resin ball to the diameter of the fiber.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ342.742;TB332

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