KINETICS AND MECHANISM OF THE BULK THERMAL POLYMERIZATION OF (3-PHENOXYPHENYL)ACETYLENE

The kinetics of the high-temperature bulk polymerization of (3-phenoxyphenyl)acetylene were examined over the temperature range 400 to 600 K, using differential scanning calorimetry. Analyses of samples polymerized over a wide range of temperature, using gel permeation chromatography, revealed that the polymer molecular weight is invariant with temperature. The absence of an observable temperature correlation for polymer molecular weight is examined in terms of a biradical mechanism in which the kinetic and molecular chain lengths are controlled by a first-order termination step involving cyclization of the growing polymer chain. Based upon the observed data and semiempirical thermochemical arguments, it is concluded that the molecular weight of poly(3-phenoxyphenyl)acetylene is controlled predominantly by steric and thermochemical factors rather than by the reaction energetics. © 1979, American Chemical Society. All rights reserved.