Pyrolysis is
a thermochemical decomposition of organic material at elevated temperatures in
the absence of oxygen (or any halogen). However, literature on the pyrolysis of
finished paper products is rare.
In the course of this study, the influence of ionic additives
(sodium, potassium, lithium, magnesium, and manganese as cations; acetate,
lactate, malate, malonate, succinate, and citrate as anions) on the pattern of
volatile pyrolysis products of finished paper was investigated. The pyrolysis
of paper caused a cascade of reaction products. As expected, the most abundant
pyrolysis product was levoglucosan, however, along with other volatile
products, such as hydroxyl and carbonyl compounds, furan and pyran derivatives,
phenols, and other anhydrosugars, respectively. These compounds could easily be
separated and characterized online using analytical pyrolysis in combination
with gas chromatography (GC) and mass spectrometry (MS) detection. Both the
composition and total amount of volatile pyrolysis products were significantly
altered when the paper samples contained metal salt ions and salts of organic
acids, respectively. Principal Component Analysis (PCA) was employed for the
multivariate analysis of the obtained pyrolysis products. This allowed for a
qualitative interpretation on how the various ionic additives affected the
formation of specific pyrolysis products. When organic acids were added onto
the paper, the pyrolysis pattern mainly depended on the protic properties of
the organic acids (mono/di/triprotic) and to a lesser extent on the type within
a protic class (monoprotic acetate or lactate vs.diprotic malate or malonate or
succinate vs. triprotic citrate).
In conclusion, the pyrolysis pattern of the paper samples was more
markedly influenced by the type of metal ions rather than by the type of
organic acid. These effects significantly depended on both the valence and the
concentration of the specific metal salt. Further investigation of this topic
will include a variation of the counter cations of various acids as well as a
concentration series for anionic additives. In addition, other counter anions
will have to be investigated in more detail in order to specifically attribute
as many effects as possible.
Article by Karin
Stadlmann, et al, from Austria.
Full access: http://mrw.so/qyHaa
Image by Peter Danilov, from
Flickr-cc.
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