Cryogenic microcrack mitigation and hydrogen permeability in a carbon fibre composite with a hybrid epoxy matrix
File(s)
Accepted version
OA Location
Author(s)
Type
Journal Article
Abstract
Carbon fibre reinforced polymer (CFRP) tanks are attractive for liquid hydrogen (LH2) storage, but cryogenic matrix microcracking can increase gas permeability and compromise reliability. This work investigates an epoxy matrix modified with core–shell rubber (CSR), nanosilica and polysulphide in carbon fibre reinforced epoxy (CFRE) laminates, providing a multiscale assessment linking cryogenic microcrack resistance and hydrogen permeability with in-situ observation of microscale damage mechanisms. The modified CFRE showed no transverse cracking up to 100 cycles and a 58% lower crack density than the unmodified system after 250 cycles between −196 °C and +55 °C. Preliminary hydrogen (H2) permeation data suggested that, after 250 cycles, microcracking increased permeability mainly through higher diffusivity rather than leakage, with X-ray computed tomography (xCT) showing no through-thickness interconnected crack network. Cryogenic scanning electron microscopy (cryo-SEM) showed no microscale matrix cracking or fibre–matrix debonding under rapid thermal shock or gradual cooling. Additional focussed ion beam–scanning electron microscopy (FIB-SEM) analysis provided evidence that isolated fibre damage can extend into the fibre interior. Under combined thermo-mechanical loading at −155 °C, the minimum measured stress at first crack was 204% higher in the modified CFRE. Overall, cryogenic microcracking mitigation in the modified CFRE depends on suppressing thermally induced microscale damage initiation, rather than on cryogenic matrix toughness or coefficient of thermal expansion (CTE) mismatch alone.
Date Issued
2026-10
Date Acceptance
2026-09-30
Citation
Composites Part B: Engineering, 2026, pp.114259-114259
ISSN
1359-8368
Publisher
Elsevier
Start Page
114259
End Page
114259
Journal / Book Title
Composites Part B: Engineering
Copyright Statement
Copyright © 2026 Elsevier. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Article Number
114259
Date Publish Online
2026-09-30