Cured samples of a nitrogen-containing acetylene-terminated resin, N,N'-( 1,3-phenylenedimethylidene) bis( 3-ethynylaniline), have been heated at lO"C/min up to 900°C in a pyroprobe attached to a gas chromatograph/mass spectrometer (GC/MS) . Analysis of the volatiles evolved during heating identified both gases and higher boiling compounds. The major higher boiling compounds are benzene, toluene, xylene, aniline, benzonitrile, rn-methylaniline, and n-methylbenzonitrile; the gases include ammonia, methane, and traces of carbon dioxide. Correlations between sample temperature and the evolution of each of these compounds have been made. The onset of all volatile formation occurs between 450 and 500°C. The higher boiling volatiles peak, then end by approximately 700"C, while the gases peak then fall off but are still being evolved a t 900°C. Average weight loss measurements of 13.6% a t 700°C and 15.7% at 900°C agree with previously published thermogravimetric analysis (TGA) data. 0 1993 John Wiley & Sons, Inc.
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There is a need for polymeric-type materials that can function at high temperatures, retain good mechanical and physical properties, and possess the advantage of being lightweight as compared to metals or ceramics. Many polymers used in high-temperature applications or as precursors to carbon have deficiencies that negatively impact the final material properties. One of the biggest problems lies in the large amounts of volatile compounds given off as the polymer or precursor is heated or carbonized. This can lead to large weight losses, low carbon yields, void formation, excessive shrinkage, and loss of mechanical strength.'.'
Typical polymers used as precursors to glassy ( nongraphitizing ) carbon are phenol-formaldehyde resins ( PFR) ,3*4 polyfurfuryl alcohol resins (PFAR) ,3-5 and rayon fiber (cellulose) .6,7 Due to the large amounts of oxygen in the original polymer structures, these materials lose H 2 0 , C 0 2 , CO, and