A study of the thermal degradation of polystyrene by thermal volatilization analysis

A TVA study of several anionic polystyrene samples, having number average molecular weights in the range of 4.6 × 103 to 2 × 106, reveals a hitherto unobserved molecular weight dependence of the overall apparent Arrhenius preexponential factor as determined by the method of Roche.2 The latter effect is discussed in terms of a model in which the zip length and chainscission rate constants are both functions of molecular weight. It is suggested that the functional dependence of the kinetic parameters on molecular weight is a reflection of their hydrodynamic coupling to the viscosity of the molten polymer.