Fickian diffusion and Flory-Rehner analysis of hydrocarbon swelling in stainless steel-integrated EPDM-UHMWPE hoses for AAR operations
Anjitha P S, Kshitija VAIDYA, Pratyush BAGARIA, Yash AVHAD, Balasubramanian KANDASUBRAMANIAN
Abstract. Air-to-air refueling (AAR) hose systems endure severe cyclic pressurization, dynamic bending, vibrational loading, and extended hydrocarbon exposure across -40 °C to 80 °C. Conventional fluorocarbon or nitrile butadiene rubber hoses reinforced with aramid fibers exhibit hydrocarbon diffusion, plasticizer migration, and interfacial delamination, compromising structural integrity and service durability. This investigation presents a novel multilayer composite incorporating ethylene propylene diene monomer (EPDM) elastomer for viscoelastic compliance and chemical resistance, austenitic SS-305 stainless steel mesh for tensile reinforcement and stress distribution, and ultra-high molecular weight polyethylene (UHMWPE) woven sheath as an effective diffusion barrier. Hot compression moulding (190 °C, 10 MPa, 60 min) with controlled cooling ensures robust interfacial bonding. Swelling tests (ASTM F146) in petrol demonstrated controlled 51% volumetric expansion within 7 hours, attaining equilibrium. Diffusion kinetics conformed to Fickian behaviour (D ≈ 0.033-0.034 mm²/h). Flory-Rehner analysis yielded χ ≈ 0.83, confirming poor solvent affinity and constrained molecular mobility. The crystalline UHMWPE sheath suppressed EPDM chain relaxation, restricted ingress, and stabilized interfaces under thermal-solvent stress. Tribological evaluation (ASTM G99, 10 N, 263.9 m) revealed stable UHMWPE-derived transfer film formation, yielding friction coefficient 0.26-0.32 and specific wear rate 1.33 × 10⁻² mm³ N⁻¹ m⁻¹, evidencing superior durability and cohesion. The EPDM-UHMWPE-SS-305 composite delivers enhanced barrier performance, wear resistance, and delamination resistance, enabling reliable indigenous AAR hose solutions.
Keywords
Multilayer Composites, Aerospace Refueling Solutions, EPDM, UHMWPE, Thermo-Mechanical Simulations, Flory-Rehner Equation
Published online 5/10/2026, 7 pages
Copyright © 2026 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: Anjitha P S, Kshitija VAIDYA, Pratyush BAGARIA, Yash AVHAD, Balasubramanian KANDASUBRAMANIAN, Fickian diffusion and Flory-Rehner analysis of hydrocarbon swelling in stainless steel-integrated EPDM-UHMWPE hoses for AAR operations, Materials Research Proceedings, Vol. 65, pp 86-92, 2026
DOI: https://doi.org/10.21741/9781644904138-13
The article was published as article 13 of the book Processing and Characterization of Materials
Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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