Study on Pyrolysis of Polystyrene by Using Gel Permeation Chromatography

Abstract

Thermal degradation of polystyrene (50 g) was carried out under an atmospheric pressure and at 240-385°C in an isothermal batch reactor.
The rates of the degradation of polystyr ene were determind by the change distribution of molecular weight measured by GPC and of the amount of volatile products. The degradation was treated as a consecutive first-order reaction such as
Relations between rate constants for the com ponents of the degradation products and time are k_a= ln c/θ, k_c= ln(1-c)/θ where A, B and C are polystyrene compounds, trimer like compounds and volatile products, respectively. The rate constants are shown below:
k_a, =1.7 2 e xp (37) X exp (-45.3 x 10³/RT ) (1/hr) and k_c=1.19 exp (39) X exp (-50 X 10³/R T) (1/hr) The ratio k_a to k_ca is k_a/k_c=0.19exp(2000/T)