Journal of Analytical and Applied Pyrolysis
62 (2002) 273–280
www.elsevier.com/locate/jaap
Thermal degradation of polystyrene wastes in
various solvents
Ali Karaduman *, Emir H. S ¸ ims ¸ek, Burhanettin C ¸ ic ¸ek,
Ali Y. Bilgesu ¨
Chemical Engineering Department, Ankara Uniersity, 06100 Tandog ˘an, Ankara, Turkey
Received 24 October 2000; accepted 7 February 2001
Abstract
Thermal polystyrene (PS) degradation was investigated in this work harnessing a high-
pressure autoclave surrounded by a furnace. n -pentane, cyclohexane (CH), and toluene were
used separately as the simplest representatives of aliphatic, cyclic, and aromatic solvents. One
experiment was solventless. Without solvent at 400 °C, waste samples accrued the weight
percentages of 32.0, 46.8, and 21.2 for the solid residue and the liquid and gaseous products
respectively. Solvent employment is strongly recommended because it almost doubled the
liquid yield while substantially reducing the solid residue to less than 5% and making the
total conversion exceed 95%. A solvent:PS ratio of around 2:1 appeared to suffice. From 350
to 450 °C, the operating temperature had only a vague effect on this phase distribution. GC
analyses identified methane, C2, C3, and C4 in the gaseous products. GC/MS results showed
that cyclohexane usage rendered liquid products of ethyl benzene, methyl ethyl benzene,
1-phenyl naphthalene 1,1-bicyclohexyl, 2-cyclohexyl ethyl benzene. Toluene employment as
solvent gave ethyl benzene, methyl ethyl benzene, 1-phenyl naphthalene propyl benzene,
1,2-dimethyl benzene. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Thermal degradation; Polystyrene; Plastic wastes; Chemical recycling
1. Introduction
Environmental and economic concerns have caused much interest in developing
new techniques to solve plastic waste problems. Landfilling, incineration, and
* Corresponding author. Tel.: +90-312-2126720 ext. 1121; fax: +90-312-2232395.
E-mail address: akrduman@science.ankara.edu.tr (A. Karaduman).
0165-2370/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
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