General purpose poly(styrene) prepared by conventional radical techniques contains a head-to-head unit as a consequence of
polymerization termination by radical coupling. As has been previously demonstrated, thermal stress promotes homolysis of
the bond linking the head-to-head components. The macroradicals generated depolymerize rapidly to generate styrene monomer.
This decomposition during processing can lead to finished articles containing objectionable levels of styrene monomer, particularly
for food packaging applications in which even low levels of monomer can promote objectionable taste and aroma. Polymer containing
no head-to-head units should not be prone to this facile decomposition. In this instance, poly(styrene) has been prepared
by nitroxyl-mediated polymerization of styrene monomer followed by reductive removal of nitroxyl end groups. Polymer prepared
in this manner contains no head-to-head units and displays thermal stability much greater than that observed for conventional
poly(styrene). A direct comparison of the stability for the two polymers is readily available by thermogravimetric techniques.
A quantitative reflection of the difference in stability is available from the rate constants for the respective decomposition.