Carbon Material Modification Of The Matrix Asphalt

Carbon-fibric-reinforced carbon composite (C/C for short) is an advanced composite with excellent physical, chemical and mechanical behavior in carbon materials, which is a kind of inorganic materials with excellent properties. However, the application and development of C/C composite have been greatly obstructed due to its high price and complicated process, which make it only applied to the aeronautic and some high-tech industries at present. Accordingly, study on C/C composite with low price and satisfactory properties has been drawn attention to many developed countries. It is crucial to develop a matrix precursor which can markedly reduce the production cost and improve the properties of the composite. In this paper, the modification of coal tar pitch as a carbon precursor is investigated. Under the action of an acid catalyst. the condensed polynuclear aromatic (CQPNA) resin is synthesized using medium梩emperture coal tar pitch and divinylbenzene (DVB) as a cross-linking agent. The resin with higher ratio of property to cost (R~~) may be used to be an excellent carbon precursor for C/C composite. The reaction mechanism has been studied with FT桰R spectrum and 1H-NMR. The microstructure of modified coal tar pitch has been studied with SEM. A great deal of mesocarbon microbead (MCMB) is found at normal temperature. In addition, the residue, which is acquired with the modified coal tar pitch treated with 5500C for two hours, has much smaller bore compared to that of the unmodified coal tar pitch. DSC, TGA and DTA have been used to analyze the structure and properties of the resin. An overall study of the effect of modification on the properties has been carried out, which follows that the modification can greatly improve the properties of coal tar pitch such as carbonization yield, soft point, density and dissolved properties. Moreover, the method of design in quadrature has been applied to optimize the experimental process, and the mathematic model is put forward to analyze various factors during test by linear multianalvsis. It is indicated that coal tar pitch can be used to synthesize COPNA resin with help of catalyst. The reaction is a positive ion梩yped condensation polymerization catalyzed by acid, in which there are two competitive reactions: some cross-linking agents produce pitch resin with the pitch, the other polymerize themselves. The latter have great effect on producing the condensed polynuclear aromatic resin (COPNA). Besides, the modified pitch has not only much mesocarbon microbead ? II ? S ABSTACT (MCMB), but also low soft point as well as high carbon yield and good thermostability. Therefore, it is qualified to be an excellent carbon precursor.