Polyphenylquinoxaline addition

Polyphenylquinoxalines (PPQ s) were first prepared in 1967 by Hergenrother (56). In 1975, Koval et al. (57,58) introduced the acetylene-terminated PPQ (ATPQ) (Pig. 10), which is the addition type of PPQ. Resembling ATPI, ATPQ also has shortcomings. The ethynl group hinders the flow of the polymer chain, and the cured ATPQ is less thermal-oxidatively stable than the comparable PPQ. The detailed status of PPQ, as well as other high-temperature adhesives, is discussed by Hergenrother (45). ... 

Polyphenylquinoxalines were cross-linked by acetylenic end-groups (Fig. 3.52), giving Tg = 321°C and good resistance to hot humid aging, but the addition of aliphatic hydrocarbon structure apparently sacrificed heat-aging resistance. Propargyl ether of bisphenol A (Fig. 3.53) was cured to a thermoset plastic with = 360°C. 

Hergenrother published additional results to compare the adhesive properties of polyphenylquinoxalines 16, 17 (Tg = 290 °C) and a polymer (Tg = 285 °C) synthesized by reacting 4,4 -carbonylbis(l,2-benzenediamine) with (1,4-phenylene)-1,1 -bis [2-phenyl-1,2-ethanedione] 12... 

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