Low-Pressure H2, NH3 Microwave Plasma Treatment of Polytetrafluoroethylene PTFE Powders: Chemical, Thermal and Wettability AnalysisReport as inadecuate




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1

Institute for Materials Research & Innovation IMRI, University of Bolton, Deane Road, Bolton BL3 5AB, UK

2

Institute of Polymer Engineering, University of Applied Sciences UAS, Northwestern Switzerland, 5210 Windisch, Switzerland

3

Center for Lipid Research, Indian Institute of Chemical Technology IICT, Hyderabad 500007, India





*

Author to whom correspondence should be addressed.



Academic Editor: Reza Montazami

Abstract Functionalization of Polytetrafluoroethylene PTFE powders of ~6 μm particle size is carried out using low-pressure 2.45 GHz H2, NH3 microwave plasmas for various durations 2.5, 10 h to chemically modify their surface and alter their surface energy. The X-ray Photoelectron Spectroscopy XPS analyses reveal that plasma treatment leads to significant defluorination F-C atomic ratio of 1.13 and 1.30 for 10 h NH3 and H2 plasma treatments, respectively vs. 1.86 for pristine PTFE, along with the incorporation of functional polar moieties on the surface, resulting in enhanced wettability. Analysis of temperature dependent XPS revealed a loss of surface moieties above 200 °C, however, the functional groups are not completely removable even at higher temperatures >300 °C, thus enabling the use of plasma treated PTFE powders as potential tribological fillers in high temperature engineering polymers. Ageing studies carried over a period of 12 months revealed that while the surface changes degenerate over time, again, they are not completely reversible. These functionalised PTFE powders can be further used for applications into smart, high performance materials such as tribological fillers for engineering polymers and bio-medical, bio-material applications. View Full-Text

Keywords: polytetrafluoroethylene PTFE; low-pressure microwave plasma; ESCA-XPS; degeneration; thermal stability polytetrafluoroethylene PTFE; low-pressure microwave plasma; ESCA-XPS; degeneration; thermal stability





Author: Harald Hunke 1, Navneet Soin 1,* , Tahir H. Shah 1, Erich Kramer 2, Alfons Pascual 2, Mallampalli Sri Lakshmi Karuna 3 and Elias Siores 1

Source: http://mdpi.com/



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