Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites
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University of Cincinnati / OhioLINK
2015
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ndltd-OhioLink-oai-etd.ohiolink.edu-ucin14280653362021-08-03T06:29:47Z Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites Akinyi, Caroline J. Environmental Engineering Carbon Nanotubes Mild digestion Polycarbonate Polyamide 6 Thermogravimetry OC EC Thermal degradation products generated during pyrolysis of carbon nanotube-poly (bisphenol A) carbonate and carbon nanotube-polyamide 6 composites were investigated using thermogravimetric analysis (TGA) techniques. The volatile and semi-volatile compounds formed during TGA of carbon nanotube (CNT) composites and their respective neat polymers were compared to assess the impact of the addition of CNTs to the polymer matrices on their thermal degradation processes. Results show that the PC-CNT composite resulted in higher concentrations of bisphenol A per milligram of sample at all temperatures studied (500-900°C) compared to the neat polymer. On the contrary, caprolactam concentrations per milligram of sample from the pyrolysis of polyamide 6 were higher than those observed from the polyamide 6-carbon nanotube composite. Kinetic parameters were computed using ASTM 1641-07 (Standard Test Method for Decomposition Kinetics by Thermogravimetry). This method is based on the assumption that the reaction obeys first order kinetics. The average kinetic parameters for the polycarbonate and its CNT composite are: activation energy, E=150±7kJ/mol, pre-exponential constant, A=9.74±12.9x108 min-1 and E=124±1kJ/mol, A=5.44±2.35 x 107 min-1 respectively. The average kinetic parameters for the polyamide 6 and its CNT composite are: E=169±8kJ/mol, A=5.27±4.87 x 1011 min-1 and E=175±7kJ/mol, A=1.73±1.23 x 1012. This is in agreement with experimental results from pyrolysis.Also as part of this research, a mild, microwave-assisted acid digestion method for CNT composites was investigated. The objective was to selectively digest the polymer matrix while leaving the nanotubes intact for quantification. Dust generated during abrasive operations (cutting, sanding, drilling) on CNT composites may expose workers to polymer particles containing CNTs. Worker exposure to the embedded CNTs can be assessed by collecting an air (or surface) sample of the dust and selectively digesting the polymer in order to quantify the nanotubes. Quantification can be performed by thermal-optical analysis for organic and elemental carbon (OC and EC), with EC being a measure of CNT mass. The OC-EC thermal profiles for the CNTs before and after digestion were unaltered. However, based on the Transmission Electron Microscopy (TEM) results, the mild digestion method investigated, while successfully digesting the polymer and leaving the CNTs in solution, physically altered the CNTs. 2015-06-19 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428065336 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428065336 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Environmental Engineering Carbon Nanotubes Mild digestion Polycarbonate Polyamide 6 Thermogravimetry OC EC |
| spellingShingle |
Environmental Engineering Carbon Nanotubes Mild digestion Polycarbonate Polyamide 6 Thermogravimetry OC EC Akinyi, Caroline J. Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| author |
Akinyi, Caroline J. |
| author_facet |
Akinyi, Caroline J. |
| author_sort |
Akinyi, Caroline J. |
| title |
Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| title_short |
Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| title_full |
Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| title_fullStr |
Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| title_full_unstemmed |
Thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| title_sort |
thermal degradation (pyrolysis) and chemical digestion of carbon nanotube polymer composites |
| publisher |
University of Cincinnati / OhioLINK |
| publishDate |
2015 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1428065336 |
| work_keys_str_mv |
AT akinyicarolinej thermaldegradationpyrolysisandchemicaldigestionofcarbonnanotubepolymercomposites |
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1719437960980463616 |