Study On Oil And Oil Finish For High Perfoemance Carbon Fiber

Carbon fiber is considered as a typical type of new industrial material widely used in high-tech areas for its excellent mechanical properties. Finish oil exclusively for carbon fiber is an indispensable auxiliary agent in the manufacturing of carbon fiber. The quality of finish oil has a direct effect on the performance of carbon fiber.With the development of the production technology of carbon fiber and the decreased production cost, carbon fiber is increasingly widely used in military and civil industries and consequently the finish oil exclusively for carbon fiber has been attracting ever-growing attention.According to current patents, a large amount of studies have been carried out on the finish oil for carbon fiber by many related companies abroad. However, the formulation of finish oil and the techniques of oil finish are confidential and not reported. The research and development of finish oil in our country are relatively backward. Therefore, it’s effective to promote the development of the finish oil exclusively for carbon fiber through analyzing imported finish oil of high quality and thus obtaining some useful information. In this thesis, thin-layer chromatography and silica gel column chromatography were employed to separate the components of imported finish oil and infrared spectroscopy was used to identify the components. Gravimetric method was conducted to quantify each component in order to provide reference for the research and development of finish oil.Considering the absence of evaluation system which is very important to the application of high quality finish oil exclusively for carbon fiber in our country, ten performance indexes that the finish oil have to possess were put forward based on the rigorous production conditions of carbon fiber and the characteristics of formation of carbon fiber precursor. Nine characterization methods for the proposed evaluation system were established and the performance of domestic and foreign finish oils was evaluated. The evaluation system can provide reference for those devoted to the research, evaluation and development of finish oil.The problem of carbon fiber ash is important as it reflects the quality of carbon fiber. In our work, the morphology of carbon fiber ash was studied using scanning electron microscopy (SEM). The main components of ash were analyzed by X-ray photoelectron spectrum (XPS) and thermal decomposition of the finish oil in the processes of preoxidation and low-temperature carbonization was analyzed using FTIR-TG The production mechanism of ash as well as the influence of performance of finish oil on the ash was comprehensively investigated.With the viewpoint of reducing the amount of ash, two-stage oil finish was recommended. Our research work demonstrated that the resultant carbon fibers finished with the technique of two-stage oil finish possessed larger density and tensile strength compared with those finished with the method of one-stage oil finish.In this thesis, technical parameters such as the temperature and concentration of oil bath and time of oil finish, etc. were discussed on the basis of the density and tensile strength of carbon fibers. The technical conditions of drying and densification were also discussed since they can affect the film forming of the finish oil on the fiber surface during the two-stage oil finish. The optimal techniques of two-stage oil finish and drying and densification were obtained in labconditions.