The thermal depolymerization of polystyrene. IV—Depolymerization in naphthalene and tetralin solutions

Abstract

The rapid decrease in molecular weight which occurs in the initial stages of the thermal degradation of polystyrene at 325°C occurs at the same rate whether the reaction is carried out in bulk polymer or in solution in naphthalene or tetralin. On the other hand, the radical chain depolymerization process which occurs in bulk polymer and in naphthalene solution, and results in the evolution of volatile products, principally monomer, dimer and trimer, is completely inhibited in tetralin solution. Thus it is deduced that volatilization and molecular weight decrease are manifestations of two distinct processes and this together with previous evidence is taken as proof that the decrease in molecular weight is due to scission of weak links rather than to an intermolecular process involving the depolymerizing free radicals.