Improved Graphite Materials for High-Temperature Aerospace Use. Volume I. Research and Development for Improved Graphite Materials.

摘要

Progress is reported on the basic studies of mechanisms of carbonization of model aromatic compounds. The survey of the thermal reactivity of model compounds has been continued with the examination by differential thermal analysis of 63 additional substituted aromatics and heterocyclics. The pyrolysis behavior of two different pitches has been examined in a thermogravimetric apparatus. Electron spin resonance (ESR) spectra have been obtained under conditions of high resolution for solutions of acenaphthylene in m-quinquephenyl. Nuclear magnetic resonance (NMR) measurements are reported for some aromatic ions, aromatic pyrolysis products, and complex raw materials for graphite. The thermal decomposition of organic diazocompounds has been investigated as an example of a pyrolysis reaction involving radical intermediates but yielding stable diamagnetic products. X-ray data have been obtained for the 002 semilattice spacing in graphite prepared from pure aromatic hydrocarbons and from complex raw materials. Molecular structure is seen to influence graphite properties, through both steric and reactivity effects Generalized reaction sequences have been prepared for the formation of graphite from the model compounds acenaphthylene and 9, 9'- bifluorenyl. The carbonization of two aromatic hydrocarbons, fluoranthene and p-terphenyl, both of which yield disordered graphite, has been investigated. The addition of carbon blacks to coking charge stocks prior to the coking operation results in cokes which have isotropic high thermal expansion characteristics. Laboratory air-blown asphalts were found to be source stocks for producing isotropic high thermal expansion graphites. Experiments in the pilot coker on thermal expansion reduction of a virgin residuum-based coke have produced low thermal expansion coke of good uniformity.