Poly(bisphenol A carbonate) or polycarbonate (PC) constitutes a significant fraction of the Waste Electrical and Electronic Equipment, mainly due to its high production and consumption rate and its variety of applications. The investigation of thermochemical methods (pyrolysis) as well as thermochemical degradation (pyrolysis) methods were employed as potential recycling method. Pyrolysis studies of polycarbonate have shown that higher pyrolysis temperatures were more suitable for PC pyrolysis, since they increased the volatile fractions (liquid and gaseous). The gaseous fraction consisted mainly of CO<sub>2</sub>, CH<sub>4</sub> and CO, whereas in the liquid fraction a large amount of different phenolic compounds, including the monomer bisphenol A was recorded. The main degradation pathway follows the scission of the isopropylidene linkage is the first step. Phenols and phenolic compounds were formed through a series of scission and hydrolysis reactions. Kinetics of PC pyrolysis are also investigated using thermogravimetric experimental data, collected at several heating rates and several either model-free (isoconversional) or model-fitting models. From the isoconversional kinetic analysis the effective activation energy was found to increase with the extent of conversion, ranging from 146 to 189 kJ/mol and from 154 to 215 kJ/mol, when using the integral method of Tang (similar to the KAS) or the differential method of Friedman, respectively. A simple first order kinetic model was found to simulate excellent the experimental data, though predicting different activation energies and pre-exponential factors at each heating rate employed.

Pyrolysis of polycarbonate-based polymer waste into useful chemical products

256th National Meeting (2018)

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