FT-Raman studies of a range of polyimides subjected to high-energy Radiations at room and elevated temperatures
- Authors: Devasahayam, Sheila , Hill, David , Connell, John
- Date: 2006
- Type: Text , Journal article
- Relation: Journal of Applied Polymer Science Vol. 101, no. 3 (2006), p. 1575-1582
- Full Text: false
- Reviewed:
- Description: A range of polyimides have been subjected to electron beam radiolysis at different temperatures. These polyimides were chemically designed to suit space applications, being either transparent or having groups which provide oxidation resistance. The structural changes that occur in the polyimides, when subjected to electron beam irradiation doses up to 18.5 MGy and up to temperatures close to their glass transition temperatures, were studied using FT-Raman spectroscopy. The range of polyimides studied included a series of perfluoropolyimides, a silicon-modified polyimide, and Ultem. The changes in the Raman peak intensities of the different groups indicated scission reactions involving the imide rings and ether linkages. (c) 2006 Wiley Periodicals, Inc.
Study of Victorian Brown Coal Dewatering by Super Absorbent Polymers using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy
- Authors: Devasahayam, Sheila , Bandyopadhyay, Sri , Hill, David
- Date: 2016
- Type: Text , Journal article
- Relation: Mineral Processing and Extractive Metallurgy Review Vol. 37, no. 4 (2016), p. 220-226
- Full Text: false
- Reviewed:
- Description: A simple and useful method to monitor the water content of coal samples using Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy is presented. ATR-FTIR analyses of oven-dried and polymer-dried brown coal samples are discussed. The difference spectra indicate that the drying of as-received coal at room temperature using a Super Absorbent Polymer (SAP) removes only 44% of moisture compared to oven drying at 105 °C. As the SAP does not completely remove the water from the coal the possibility of explosion due to oxidation of the coal powder is greatly reduced. SAP drying is energy and emission efficient compared to oven drying method. At the pH < 5 studied SAP dewatering is dominated by physical processes. The movements in H-bonding observed in ATR-FTIR suggest a physico-chemical process. © 2016 Taylor & Francis.