INFLUENCE OF CONDITIONS OF STRETCHING AND GAS MEDIA UNDER GRAPHITATION ON CRYSTALLINE STRUCTURE AND PROPERTIES OF HIGH-MODULUS CARBON FIBERS BASED ON POLYACRYLONITRILE

Autor: Leonid M. Buchnev, Vladimir M. Samoylov, Nina N. Steparyova, Dmitry B. Verbets, Igor A. Bubnenkov, Anastasiya V. Nakhodnova
Rok vydání: 1970
Předmět:
Zdroj: IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA. 61
ISSN: 2500-3070
0579-2991
DOI: 10.6060/ivkkt.20186111.17y
Popis: The effect of stretching ratio and the gaseous medium on graphitization on the crystal structure and properties of high-modulus carbon fibers (CFs) based on polyacrylonitrile was studied. It is shown that an increase in the degree of stretching ratio to 8-10.5% of the initial high-strength CFs at a temperature of 3000 °С leads to a decrease in the tensile strength and an increase in the modulus of elasticity CFs. The use of a halogen-hydrocarbons containing medium at a graphitization temperature of 2500 °C did not lead to a decrease in the strength of the obtained CFs, but led to a significant increase in the modulus of elasticity CFs up to 59%. The crystal structure of the obtained CFs was studied by X-ray structural analysis and Raman spectroscopy. It is shown that with an increase in stretching ratio up to 8%, a decrease in the interlayer distance d002, an increase in the height Lc, and the diameter of the La crystallites are observed. Raman spectroscopy showed that the ID/IG parameter (the ratio of the integrated intensities of the spectral bands D and G) decreases, which also corresponds to an increase in the degree of perfection of the CFs crystal structure. The diffraction pattern shows the effect of a halogen-hydrocarbons containing medium at a graphitization temperature of 2500 °C on the CFs crystal structure: a decrease in the half-width of the 002 peak is observed, although the interlayer distance does not decrease, and the ratio of the ID/IG spectral intensities is observed on the Raman spectrum, which confirms a higher degree of crystalline structures for CFs that have undergone graphitization in a halogen- hydrocarbons containing medium.
Databáze: OpenAIRE
Externí odkaz: