Kinetic Study On The Thermal Degradation Of Polyvinylpyrrolidone (Pvp)
Thermogravimetric analysis (TGA) data (thermogravimetric curves TG and derivative thermogravimetric curves DTG) were used to provide an alternative model of the kinetics of plastics waste degradation to the current model based on molecular weight distribution (MWD) measurement. TGA models tradit...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English English |
| Published: |
2003
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/12151/1/FK_2003_10.pdf |
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| Summary: | Thermogravimetric analysis (TGA) data (thermogravimetric curves TG and
derivative thermogravimetric curves DTG) were used to provide an alternative model
of the kinetics of plastics waste degradation to the current model based on molecular
weight distribution (MWD) measurement.
TGA models traditionally consist of assumed 'pseudo first order' kinetic
equations. The thermal degradation kinetics of polyvinylpyrrolidone (PVP) was
investigated by dynamic thermogravimetry, in a nitrogen atmosphere, over the
temperature range 25-800 °c and at constant nominal heating rates of 5 , 1 0, 20, and
30 °C/min, respectively. Two distinct mass change stages in the thermogravimetric
analysis (TGA) curves indicated that the degradation of polyvinylpyrrolidone (PVP) might be attributed to two reactions. The method developed to accommodate this
kinetic study involved treating the data as a pseudo first-order reaction. The
corresponding activation energies, frequency factors and reaction orders of the two
reactions were determined. The TG thermgrams (TGA curves and DTG curves)
obtained from TGA showed the same shape and trend at different heating rates of 5,
1 0, 20, and 30°C/min.
To accommodate this mechanism change, the data were treated as pseudo
first-order reaction. A single first-order fit provided a good correlation of the data
obtained at different heating rate for polyvinylpyrrolidone (PVP).
A simple relationship was developed to predict the activation energy for the
pyrolysis process. The activation energy was found to be in good agreement with
past experimental using polyvinylpyrrolidone (PVP). |
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