The Synthesis and Thermal Properties of Isomeric Acetylene Terminated Quinoxalines
Final rept. Jan 1979-Jun 1981
AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH
Pagination or Media Count:
A mixture of the halogenated quinoxaline isomers, 3-3-bromophenyl- 2-phenyl-6-iodoquinoxaline and 2-3-bromophenyl-3-phenyl-6-iodoquinoxaline, was synthesized and the two isomers were separated and purified. A substantial difference in solubility and melting point behavior was found between the isomers. The halogen terminated isomers were converted individually to the corresponding isomeric acetylene terminated quinoxalines which exhibited analogous solubility and melting point differences. The glass transition temperatures of the individual acetylene terminated quinoxalines and of various mixtures all fell within a range from 33 C to 54C. The presence of isomer mixtures was found to inhibit reversion from the amorphous state to the crystalline state. The significance of this effect and of solubility and melting point differences with respect to melt processing of acetylene terminated quinoxaline resin systems is discussed.
- Physical Chemistry
- Polymer Chemistry