| Abstract: | A series of acetylene-terminated phenylquinoxaline oligomers have been prepared which cure by addition, without the evolution of volatiles. The synthesis utilized the novel terminal acetylene end-capping reagent, 3-(3,4-diaminophenoxy)phenylacetylene. The end-capped oligomers were soluble (20–30%) in low-boiling organic solvents and exhibited a high degree of flow at their softening temperatures. Thermal analytical data obtained on the oligomers indicated initial softening in the vicinity of 160°C and a strong polymerization exotherm reaching a maximum at 274°C. Cured samples (8 hr at 280°C) exhibited Tg values of approximately 320°C. Mass spectrometry–thermogravimetric analysis of the polymers demonstrated that no volatiles were emitted during cure, and that decomposition of the resins initiated at 465°C. Synthetic routes to the acetylene terminated phenylquinoxaline oligomers and the end-capping reagent are discussed as well as the physical properties of the oligomer and cured system. |
