THERMOMECHANICAL BEHAVIOR OF A POLYPHENYLIMIDE-QUINOXALINE

Linear polyphenylimide-quinoxalines (PPIQ) can be crosslinked by isothermal heat treatment in an inert atmosphere. To show this, three polyphenylimide-quinoxalines were prepared which differed only in molecular weight and polymer chain endings. Apparent activation energies of thermal crosslinking were then obtained from the rates of change of T//g as a function of time and temperature. Differences in polymer molecular weight had a distincct effect on the rates of change of T//g, but the polymer chain ends seemed to have a lesser effect than previously observed on polyphenylquinoxalines (PPQ). The rate of change in T//g is greater for PPIQ than for PPQ of a similar molecular weight.