The kinetics of the global primary thermal decomposition of poly-(ethylene
terephthalate) (PET) waste was studied in strict pyrolysis conditions and w
ith different proportions of oxygen by TGA, between temperatures of 25 and
800 degreesC. Prior to the decomposition, the polymer first melts at around
250 degreesC. The pyrolysis of PET, which starts at 400 degreesC, is model
ed assuming that it is formed by two different parts which decompose by two
independent reactions. The introduction of oxygen produces the appearance
of a new process, which does not start until the pyrolysis finishes. This f
act is interpreted as the combustion reaction of the char formed in the pyr
olysis, and was modeled kinetically with a common combustion reaction to th
e solid char residues obtained from each initial fraction. One pyrolysis ru
n and one combustion run at 850 degreesC, at fuel-rich conditions were carr
ied out to analyze the different gas compositions evolved, where an appreci
able amount of poly aromatic hydrocarbons (PAH) was detected. (C) 2001 Else
vier Science B.V. All rights reserved.