Low-Pressure H2, NH3 Microwave Plasma Treatment of Polytetrafluoroethylene (PTFE) Powders: Chemical, Thermal and Wettability Analysis

Materials

Harald Hunke¹  Navneet Soin¹  Tahir H. Shah¹  Erich Kramer³  Alfons Pascual³  Mallampalli Sri Lakshmi Karuna²  Elias Siores¹ 

[1] Institute for Materials Research & Innovation (IMRI), University of Bolton, Deane Road, Bolton BL3 5AB, UK; E-Mails:;Center for Lipid Research, Indian Institute of Chemical Technology (IICT), Hyderabad 500007, India; E-Mail:;Institute of Polymer Engineering, University of Applied Sciences (UAS), Northwestern Switzerland, 5210 Windisch, Switzerland; E-Mails:

关键词: polytetrafluoroethylene (PTFE);    low-pressure microwave plasma;    ESCA/XPS;    degeneration;    thermal stability;   

DOI  :  10.3390/ma8052258

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.