Wyniki wyszukiwania - BazTech

Ograniczanie wyników

1 Polish Journal of Chemical Technology

1 2001

Znaleziono wyników: 1

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: Qi-free pitch

Sortuj według:

Ogranicz wyniki do:

High softening point pitches produced by air-blowing of Qi-free coal-tar derived precursors

Machnikowski J., Gerus-Piasecka I., Kubica K., Machnikowska H.

Polish Journal of Chemical Technology

2001

Vol. 3, nr 2

11-16

Modified pitches with the softening point of about 220°C were prepared by air-blowing at 300°C of Qi-free pitches from commercial "light" and "heavy" coke-oven tars. The effect of parent tar nature and Qi-free tar distillation conditions on air-blowing behaviour was studied using solvent and extrographic fractionation, elemental analysis, 1H NMR, and contact angle measurement. The kinetics and the mechanism of the mesophase formation on isothermal treatment at 450°C and the optical texture of semi-cokes were studied by polarized-light optical microscopy. Under these conditions totally isotropic pitches of considerably enhanced coking yield and TI content with very little change in elemental composition produced. The air-blowing accelerated the formation of mesophase on carbonization without marked affecting the mesophase units growth and the flow type optical texture of semicoke. The pitch from Qi-free "heavy" tar distilled under the reduced pressure was selected as most suitable potential precursor for isotropic carbon fibers.