Surface and bulk properties of severely fluorinated carbon fibres

Kingsley K.C. Ho; Graham Beamson; George Shia; Natalya V. Polyakova; Alexander Bismarck

doi:10.1016/j.jfluchem.2007.06.005

Surface and bulk properties of severely fluorinated carbon fibres

Kingsley K.C. Ho, Graham Beamson, George Shia, Natalya V. Polyakova, Alexander Bismarck (Corresponding author)

Publications: Contribution to journal › Article › Peer Reviewed

Abstract

The development of ultra-inert composites using fluorinated carbon fibres as the reinforcement requires fluorinated carbon fibres with a durable surface composition. Here we report the effect of direct fluorination using an F₂/N₂ mixture at 653 K on the surface and bulk properties of two types of high strength carbon fibres. These were treated up to a surface fluorine content of ∼64 at.% and a bulk fluorine content of ∼15 mass%. A colour change was observed after fluorination caused by the changes in the graphitic band structure of the carbon fibres by the introduction of carbon sp³ hybridisation. The tensile strength and Young's modulus decrease after fluorination by up to 33 and 22%, respectively. XRD shows marginal changes in the interlayer distance but the crystallite size increases. Changes in the electrical conductivity of the fluorinated carbon fibres indicate that the modification is confined to the near surface volume. Predominantly covalent C-F bonds are formed as shown by X-ray photoelectron spectroscopy (XPS) and measured zeta (ζ)-potentials. Hence the fluorinated fibres are hydrophobic and have low surface tensions. This and the large increase in fibre surface area, as determined by nitrogen adsorption, is expected to facilitate interfacial interaction between fluorinated carbon fibres and fluoropolymers.

Original language	English
Pages (from-to)	1359-1368
Number of pages	10
Journal	Journal of Fluorine Chemistry
Volume	128
Issue number	11
DOIs	https://doi.org/10.1016/j.jfluchem.2007.06.005
Publication status	Published - Nov 2007
Externally published	Yes

Funding

Our research was made possible by the financial support of the UK Engineering and Physical Science Research Council (EPSRC) (Grant Award No.: GR/S75673/01). We would like to thank Vladimir Arye for arranging and assisting with shipping and fluorinating the fibre samples (Lodester, Inc., Howell, NJ, USA). We thank Michael Q. Tran ( PaCE , Imperial College London) for taking the SEM images. We also acknowledge the support of the STFC (Daresbury Laboratory, Warrington, UK) for enabling the XPS characterisation of the fluorinated carbon fibres.

Austrian Fields of Science 2012

205019 Material sciences
103018 Materials physics

Keywords

Carbon fibres
Contact angle
Direct fluorination
Surface and bulk properties
XPS
Zeta potential

Access to Document

10.1016/j.jfluchem.2007.06.005

Cite this

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title = "Surface and bulk properties of severely fluorinated carbon fibres",

abstract = "The development of ultra-inert composites using fluorinated carbon fibres as the reinforcement requires fluorinated carbon fibres with a durable surface composition. Here we report the effect of direct fluorination using an F2/N2 mixture at 653 K on the surface and bulk properties of two types of high strength carbon fibres. These were treated up to a surface fluorine content of ∼64 at.\% and a bulk fluorine content of ∼15 mass\%. A colour change was observed after fluorination caused by the changes in the graphitic band structure of the carbon fibres by the introduction of carbon sp3 hybridisation. The tensile strength and Young's modulus decrease after fluorination by up to 33 and 22\%, respectively. XRD shows marginal changes in the interlayer distance but the crystallite size increases. Changes in the electrical conductivity of the fluorinated carbon fibres indicate that the modification is confined to the near surface volume. Predominantly covalent C-F bonds are formed as shown by X-ray photoelectron spectroscopy (XPS) and measured zeta (ζ)-potentials. Hence the fluorinated fibres are hydrophobic and have low surface tensions. This and the large increase in fibre surface area, as determined by nitrogen adsorption, is expected to facilitate interfacial interaction between fluorinated carbon fibres and fluoropolymers.",

keywords = "Carbon fibres, Contact angle, Direct fluorination, Surface and bulk properties, XPS, Zeta potential",

author = "Ho, \{Kingsley K.C.\} and Graham Beamson and George Shia and Polyakova, \{Natalya V.\} and Alexander Bismarck",

note = "Funding Information: Our research was made possible by the financial support of the UK Engineering and Physical Science Research Council (EPSRC) (Grant Award No.: GR/S75673/01). We would like to thank Vladimir Arye for arranging and assisting with shipping and fluorinating the fibre samples (Lodester, Inc., Howell, NJ, USA). We thank Michael Q. Tran ( PaCE , Imperial College London) for taking the SEM images. We also acknowledge the support of the STFC (Daresbury Laboratory, Warrington, UK) for enabling the XPS characterisation of the fluorinated carbon fibres. Copyright: Copyright 2007 Elsevier B.V., All rights reserved.",

year = "2007",

month = nov,

doi = "10.1016/j.jfluchem.2007.06.005",

language = "English",

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journal = "Journal of Fluorine Chemistry",

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AU - Beamson, Graham

AU - Shia, George

AU - Polyakova, Natalya V.

AU - Bismarck, Alexander

N1 - Funding Information: Our research was made possible by the financial support of the UK Engineering and Physical Science Research Council (EPSRC) (Grant Award No.: GR/S75673/01). We would like to thank Vladimir Arye for arranging and assisting with shipping and fluorinating the fibre samples (Lodester, Inc., Howell, NJ, USA). We thank Michael Q. Tran ( PaCE , Imperial College London) for taking the SEM images. We also acknowledge the support of the STFC (Daresbury Laboratory, Warrington, UK) for enabling the XPS characterisation of the fluorinated carbon fibres. Copyright: Copyright 2007 Elsevier B.V., All rights reserved.

PY - 2007/11

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N2 - The development of ultra-inert composites using fluorinated carbon fibres as the reinforcement requires fluorinated carbon fibres with a durable surface composition. Here we report the effect of direct fluorination using an F2/N2 mixture at 653 K on the surface and bulk properties of two types of high strength carbon fibres. These were treated up to a surface fluorine content of ∼64 at.% and a bulk fluorine content of ∼15 mass%. A colour change was observed after fluorination caused by the changes in the graphitic band structure of the carbon fibres by the introduction of carbon sp3 hybridisation. The tensile strength and Young's modulus decrease after fluorination by up to 33 and 22%, respectively. XRD shows marginal changes in the interlayer distance but the crystallite size increases. Changes in the electrical conductivity of the fluorinated carbon fibres indicate that the modification is confined to the near surface volume. Predominantly covalent C-F bonds are formed as shown by X-ray photoelectron spectroscopy (XPS) and measured zeta (ζ)-potentials. Hence the fluorinated fibres are hydrophobic and have low surface tensions. This and the large increase in fibre surface area, as determined by nitrogen adsorption, is expected to facilitate interfacial interaction between fluorinated carbon fibres and fluoropolymers.

AB - The development of ultra-inert composites using fluorinated carbon fibres as the reinforcement requires fluorinated carbon fibres with a durable surface composition. Here we report the effect of direct fluorination using an F2/N2 mixture at 653 K on the surface and bulk properties of two types of high strength carbon fibres. These were treated up to a surface fluorine content of ∼64 at.% and a bulk fluorine content of ∼15 mass%. A colour change was observed after fluorination caused by the changes in the graphitic band structure of the carbon fibres by the introduction of carbon sp3 hybridisation. The tensile strength and Young's modulus decrease after fluorination by up to 33 and 22%, respectively. XRD shows marginal changes in the interlayer distance but the crystallite size increases. Changes in the electrical conductivity of the fluorinated carbon fibres indicate that the modification is confined to the near surface volume. Predominantly covalent C-F bonds are formed as shown by X-ray photoelectron spectroscopy (XPS) and measured zeta (ζ)-potentials. Hence the fluorinated fibres are hydrophobic and have low surface tensions. This and the large increase in fibre surface area, as determined by nitrogen adsorption, is expected to facilitate interfacial interaction between fluorinated carbon fibres and fluoropolymers.

KW - Carbon fibres

KW - Contact angle

KW - Direct fluorination

KW - Surface and bulk properties

KW - XPS

KW - Zeta potential

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DO - 10.1016/j.jfluchem.2007.06.005

M3 - Article

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SN - 0022-1139

VL - 128

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EP - 1368

JO - Journal of Fluorine Chemistry

JF - Journal of Fluorine Chemistry

IS - 11

ER -

Surface and bulk properties of severely fluorinated carbon fibres

Abstract

Funding

Austrian Fields of Science 2012

Keywords

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