Dual-surface engineering of carbon fibers by grafting carbon nanotubes and chemical functionalization
File(s)
Published version
Author(s)
Type
Conference Paper
Abstract
Carbon fiber-reinforced polymer (CFRP) composites, performance remains constrained by fiber–matrix adhesion due to the chemically inert and smooth surfaces of the untreated fibers (CFs). Chemical
compatibility is usually improved by electro-oxidation followed by sizing to improve the mechanical properties, particularly in epoxy-matrix composites. Grafting carbon nanotubes (CNTs) onto CFs by chemical vapour deposition (CVD) improves mechanical interlocking but generates a chemically inert surface. This study shows that combining CNT grafting with a simple chemical treatment (sizing or epoxidation) activates the surface and maximises interfacial strength between epoxy matrix and modified fibers. Surface analysis confirmed increased oxygen content and polarity from these treatments. Single-fiber pull-out tests demonstrated that sized CNT-g-CF in an epoxy matrix achieved up to 60% higher interfacial shear strength than both unsized CFs and as-produced (unsized) CNT-g-CF. Flexural testing of unidirectional fiber reinforced epoxy composite rods (40% Vf) showed a 30% increase in flexural strength compared to unsized CFs and an 8% gain over as-produced (unsized) CNT-g-CFs. These results highlight that chemical modification is essential to fully exploit the potential of CNT-enhanced interfaces in epoxy-based matrices.
compatibility is usually improved by electro-oxidation followed by sizing to improve the mechanical properties, particularly in epoxy-matrix composites. Grafting carbon nanotubes (CNTs) onto CFs by chemical vapour deposition (CVD) improves mechanical interlocking but generates a chemically inert surface. This study shows that combining CNT grafting with a simple chemical treatment (sizing or epoxidation) activates the surface and maximises interfacial strength between epoxy matrix and modified fibers. Surface analysis confirmed increased oxygen content and polarity from these treatments. Single-fiber pull-out tests demonstrated that sized CNT-g-CF in an epoxy matrix achieved up to 60% higher interfacial shear strength than both unsized CFs and as-produced (unsized) CNT-g-CF. Flexural testing of unidirectional fiber reinforced epoxy composite rods (40% Vf) showed a 30% increase in flexural strength compared to unsized CFs and an 8% gain over as-produced (unsized) CNT-g-CFs. These results highlight that chemical modification is essential to fully exploit the potential of CNT-enhanced interfaces in epoxy-based matrices.
Date Issued
2026-02-10
Date Acceptance
2025-05-01
Citation
2026
Publisher
The University of Delaware
Copyright Statement
© 2025 The Author(s). This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-sa/4.0/).
License URL
Source
24th International Conference on Composite Materials (ICCM-24)
Publication Status
Published
Start Date
2025-08-04
Finish Date
2025-08-08
Coverage Spatial
Baltimore, MD, USA
Date Publish Online
2026-02-10