Low-pressure H2, NH3 microwave plasma treatment of Polytetrafluoroethylene (PTFE) powders: Chemical, thermal and wettability analysis

Harald Hunke, Navneet Soin, Tahir H. Shah, Erich Kramer, Alfons Pascual, Mallampalli Sri Lakshmi Karuna, Elias Siores

Research output: Contribution to journalArticle

20 Citations (Scopus)

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.

LanguageEnglish
Pages2258-2275
Number of pages18
JournalMaterials
Volume8
Issue number5
DOIs
Publication statusPublished - 28 Apr 2015

Fingerprint

Polytetrafluoroethylene
Polytetrafluoroethylenes
Powders
Wetting
Microwaves
Plasmas
Fillers
Polymers
X ray photoelectron spectroscopy
High temperature engineering
Interfacial energy
Functional groups
Aging of materials
Particle size
Temperature
Hot Temperature

Keywords

  • Degeneration
  • ESCA/XPS
  • Low-pressure microwave plasma
  • Polytetrafluoroethylene (PTFE)
  • Thermal stability

Cite this

Hunke, Harald ; Soin, Navneet ; Shah, Tahir H. ; Kramer, Erich ; Pascual, Alfons ; Karuna, Mallampalli Sri Lakshmi ; Siores, Elias. / Low-pressure H2, NH3 microwave plasma treatment of Polytetrafluoroethylene (PTFE) powders : Chemical, thermal and wettability analysis. In: Materials. 2015 ; Vol. 8, No. 5. pp. 2258-2275.
@article{5125ed44c9ab4ef6922257346edcefe9,
title = "Low-pressure H2, NH3 microwave plasma treatment of Polytetrafluoroethylene (PTFE) powders: Chemical, thermal and wettability analysis",
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.",
keywords = "Degeneration, ESCA/XPS, Low-pressure microwave plasma, Polytetrafluoroethylene (PTFE), Thermal stability",
author = "Harald Hunke and Navneet Soin and Shah, {Tahir H.} and Erich Kramer and Alfons Pascual and Karuna, {Mallampalli Sri Lakshmi} and Elias Siores",
year = "2015",
month = "4",
day = "28",
doi = "10.3390/ma8052258",
language = "English",
volume = "8",
pages = "2258--2275",
journal = "Materials",
issn = "1996-1944",
publisher = "MDPI",
number = "5",

}

Low-pressure H2, NH3 microwave plasma treatment of Polytetrafluoroethylene (PTFE) powders : Chemical, thermal and wettability analysis. / Hunke, Harald; Soin, Navneet; Shah, Tahir H.; Kramer, Erich; Pascual, Alfons; Karuna, Mallampalli Sri Lakshmi; Siores, Elias.

In: Materials, Vol. 8, No. 5, 28.04.2015, p. 2258-2275.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Low-pressure H2, NH3 microwave plasma treatment of Polytetrafluoroethylene (PTFE) powders

T2 - Materials

AU - Hunke, Harald

AU - Soin, Navneet

AU - Shah, Tahir H.

AU - Kramer, Erich

AU - Pascual, Alfons

AU - Karuna, Mallampalli Sri Lakshmi

AU - Siores, Elias

PY - 2015/4/28

Y1 - 2015/4/28

N2 - 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.

AB - 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.

KW - Degeneration

KW - ESCA/XPS

KW - Low-pressure microwave plasma

KW - Polytetrafluoroethylene (PTFE)

KW - Thermal stability

UR - http://www.scopus.com/inward/record.url?scp=84930665082&partnerID=8YFLogxK

U2 - 10.3390/ma8052258

DO - 10.3390/ma8052258

M3 - Article

VL - 8

SP - 2258

EP - 2275

JO - Materials

JF - Materials

SN - 1996-1944

IS - 5

ER -