The Correlative Study Of Preparation Of High-Performance Polyacrylonitrile Based Activated Carbon Fibers

In the 1970s, activated carbon fibers (ACF) has been widely used as adsorption material in people's daily life. This kind of fibers have high specific surface area, narrow distribution of pore-size and rich in micro-pore structure. They also have efficient adsorption and desorption ability, excellent adsorption performance and great kinetics performance. Expecially polyacrylonitrile (PAN) based activated carbon fibers not only have all the excellent properties, but also have high nitrogen content and mechanical properties. So more and more researchers begin to do the study on PAN-ACF because of its excellent performance.Most traditional PAN based carbon fibers have been prepared by intermittent preparation methods. Continuous preparation methods have been mainly used to manufacture PAN based carbon fiber cloth or blanket. But the requirement of continuous preparation equipment is strict, and the quality of the product is unstable. Traditional continuous preparation of PAN based carbon fiber cloth or blanket adopt physical activation, especially the water steam and carbon dioxide activation. Chemical activation method for preparation of PAN based carbon fiber usually is intermittent. And the PAN based activated carbon fibers by traditional preparation method have poor strength and easily become power.The main purpose of this study is to implement continuous efficient preparation of monofi lament cluster of PAN based carbon fiber. In this study we want to find a new activation method to manufacture 12K PAN based activated carbon fibers, and the fibers have excellent adsorption and mechanical performance. In this study, the 12K PAN fibers produced by British Courtaulds Company are used to produce PAN-based activated carbon fibers via a special designed continuous online production system. The precursor is treated by air atmosphere preoxidation, through four temperature zones, in each temperature zone stay 20 minutes under the range of 200?300?. The activation process of this study are mainly the steam activation, KOH activation and the synergistic activation. The most important of activation experiment is to reasonably set active process and control the degree of activation, in order to make sure the activated carbon fibers maintain fiber morphology and receive samples stablely.In this study, there are three preparation methods:activated pre-carbonization fibers by steam; activated pre-oxidation fibers by steam; activated preoxidation by KOH and steam. And we can call the above-mentioned three samples as the "two-step PAN-ACF", "one-step PAN-ACF" and "collaborative activation PAN-ACF". By comparing three kinds of preparation process and their corresponding three samples'mechanics and adsorption performance, we can explore the best preparation technology.The results showed that the "collaborative activation PAN-ACF" has more excellent pore structure and adsorption performance, but the corresponding fibers'strength and maximum load are lower than the other samples. And the preparation process of activated preoxidation by KOH and steam is more complex than others, also more strict to parameters. "One-step PAN-ACF" has the better mechanical strength and adsorption performance than "two-step PAN-ACF". And the preparation process of activated preoxidation fibers by steam is easier than others. Compared with the "two-step PAN-ACF", "one-step PAN-ACF" can not only improve the efficiency, save energy, but also make sure the activated carbon fibers maintain fiber morphology and receive samples stablely.