THERMAL POLYMERIZATION OF ARYLACETYLENES - A STEPWISE ACTIVATED MONOMER MECHANISM

Kinetics of the thermal polymerization of ATR(acetylene-terminated resin) model compounds, bisphenol A monobenzyl mono(ethynylaryl) ethers, was studied by means of GPC and the resulting oligomers were characterized by FTIR, UV, and H-1 NMR techniques. It was found that monomer was consumed rapidly at first, and later slowly, yielding a mixture of dimer, low oligomers (DP less-than-or-equal-to 6) and higher ones. The concentrations of every lower species remained nearly constant throughout the polymerization (except first ten minutes). In order to account for these results, a new mechanism involving the activation of monomer and its attack on the end unit of the polymer chain was proposed. This is the first example of activated monomer mechanism (a.m. mechanism) for non-catalyzed polymerization of unsaturated monomers and, at the same time, the first example of stepwise a.m. mechanism. The structure of the resulting polymer will be discussed on the basis of this mechanism.