Accession Number : AD0739284

Title :   About the Forming of the Structure of Pyrolytic Carbonic Fibers,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Ermolenko,I. N. ; Sviridova,R. N.

Report Date : 12 NOV 1971

Pagination or Media Count : 10

Abstract : Rayon fibers are oxidized with N oxides to poly(anhydrouronic acids) which are converted to the Al salts. The pyrolysis of fibers containing 11.5 percent COOH groups is carried out in a vacuum up to 850 degrees by raising the temperature at a 4 degrees minimum rate. Higher yields of carbon fibers with higher rigidity are obtained from rayons containing higher proportion of the COOH groups. Oxidation to 50 percent give optimal properties and yields. The pyrolysis temperature strength relation shows a minimum strength at 200 degrees and a substantial increase in the strength at 800- 850 degrees. Gas adsorption and the IR study demonstrate that the carbon fibers represent a highly packed structure of oriented molecules. Preoxidation and Al-salts enhance the formation of oriented structures. Slower rate of temperature raise during the pyrolysis or longer heating at 800 degrees, as well as drawing the fibers during the pyrolysis, increase the mechanical strength of the carbon fibers. (Author, modified-PL)

Descriptors :   (*CARBON FIBERS, SYNTHESIS(CHEMISTRY)), (*RAYON, *PYROLYSIS), OXIDATION, USSR

Subject Categories : Textiles

Distribution Statement : APPROVED FOR PUBLIC RELEASE