화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.41, No.22, 5337-5340, 2002
Kinetics of degradation of polycarbonate in supercritical and subcritical benzene
The degradation kinetics of polycarbonate [poly(Bisphenol A carbonate)] in supercritical and subcritical benzene was studied at various temperatures (523-618 K) at 50 atm. The degradation was also investigated in other solvents at 573 K and 50 atm. The time evolution of molecular weight distribution was obtained by gel permeation chromatography and modeled with continuous distribution kinetics to obtain the degradation rate coefficients. The activation energy, determined from the temperature dependence of the rate coefficient, increased from 16.7 to 20.4 kcal/mol from the subcritical region to the supercritical region of the solvent. The degradation rate coefficients at the supercritical conditions were an order higher than the rate coefficients at subcritical conditions, indicating enhanced degradation at supercritical conditions. The Arrhenius plot showed a break at the supercritical transition point, whereas the semilogarithmic plot of rate coefficients with the density of the reaction mixture showed a continuous linear variation.