Sohail Yasin

Trenchless rehabilitation of urban district heating pipelines places stringent requirements on the hygrothermal durability of liner materials. In this work, ethylene propylene diene monomer (EPDM) was used to fabricate fiber‐reinforced liner pipes containing a small amount of deep eutectic solvent (DES), and accelerated aging tests were conducted in saturated steam at 180°C and 200°C. Thermogravimetric analysis (TGA), oxidation induction time (OIT), crosslink density, tensile testing, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to evaluate the thermal response, residual oxidative stability, network structure, representative tensile response, spectral evolution, and visible morphology of the composite liners. The results show that the incorporation of DES increased the initial crosslink density and tensile response of the EPDM system. In the unaged state, the crosslink density increased from 6.64 × 10 ⁻⁵ to 8.22 × 10 ⁻⁵ mol/cm ³ , while the tensile strength and elongation at break increased from 9.70 MPa and 254.08% to 12.57 MPa and 292.28%, respectively. After aging at 180°C for 10 days, the DES‐containing sample retained a higher residual absolute tensile response and network compactness. Under the more severe 200°C condition, this advantage became less pronounced. OIT, FTIR, and SEM results are interpreted as supportive evidence for condition‐dependent structural evolution. These findings suggest that DES modification can improve the steam‐aging durability of fiber‐reinforced EPDM composites within a defined temperature window, while its benefit is attenuated under severe saturated‐steam aging.

Eco-conception de fin de vie des textiles ignifugés: Les différentes phases du cycle de vie des textiles ignifugés (TIgni) ont des impacts importants sur l'environnement. Nombreuses études réalisées se sont principalement axées sur des méthodes de synthèse des molécules d’ignifugation. Cependant la phase de fin de vie des TIgni a été longtemps négligée, et nécessite aujourd’hui une attention particulière. Alors que la valorisation des déchets par incinération est une voie appropriée pour la gestion des déchets textiles, les TIgni posent des problèmes car les espèces ignifuges diminuent le rendement énergétique dans le processus d'incinération en raison d'une combustion incomplète et émettent des fumées toxiques. Nous proposons une méthode plus écologique de valorisation énergétique de ces déchets, par la dégradation et l'élimination préalable des substances ignifuges permanentes organophosphorés (MPDA) des textiles, en utilisant le procédé d'oxydation avancé (AOP) de Fenton. Ensuite, la valorisation thermique est réalisée par gazéification au lieu de l'incinération. La cinétique de dégradation de la MDPA, suivie en mesurant la DCO, semble dépendre des concentrations en réactifs de Fenton. Après ce traitement, les propriétés mécaniques du coton restent inchangées. Le test d'inflammabilité et les résultats thermogravimétriques (TGA, DTG et PCFC) confirment la dégradation du MDPA.Les résultats de gazéification montrent des propriétés de combustion accrues des textiles ignifuges après ce traitement qui permet donc d’éco-concevoir la valorisation énergétique de ces textiles. L’évaluation des impacts environnementaux réels en utilisant l’ACV permet de confirmer l’éco-conception de fin de vie des produits textiles ignifugés.

Rubber materials undergo continuous wear in high-pressure seal applications. To address the risk of adhesive wear and consequent leakage of rubber seals operating under reciprocating sliding in high-pressure hydrogen storage and refueling systems, this study employed high-pressure hydrogen tribology testing. Ball-on-disk reciprocating tests were conducted using a 316L stainless-steel ball against silica-filled nitrile butadiene rubber (NBR), and the friction response and wear-morphology evolution were compared under ambient air, 1 MPa hydrogen (H₂), 50 MPa H₂, 50 MPa nitrogen (N₂), and grease-coated conditions. Under dry sliding, the coefficient of friction (COF) of NBR in air and hydrogen ranged from 1.34 to 1.44, whereas it decreased markedly to 0.942 in 50 MPa N₂. The wear volume under the four dry conditions was concentrated in the range of ~0.292–0.320 mm³. After grease coating, the steady-state COF in air and at 50 MPa H₂ dropped to 0.099 and 0.105, respectively, and the wear features changed from ridge-like wear patterns/tear pits to regular, smooth indentations with slight running marks. The results demonstrate that a lubricating film can effectively separate direct metal–rubber contact and suppress stick–slip, enabling a low-friction, low-wear, and highly stable interface in high-pressure hydrogen, and providing a practical engineering route for reliable operation of rubber seals in hydrogen service.

Rubber O-rings play a crucial role in ensuring the safety and reliability of high-pressure hydrogen systems. However, their degradation and failure under hydrogen exposure remain a major barrier to the long-term stability of sealing structures. This review summarizes the failure modes of rubber O-rings in high-pressure hydrogen environments and clarifies the interaction mechanisms among hydrogen permeation, swelling, rapid gas decompression (RGD), and mechanical fatigue. Compared with conventional high-pressure gases, hydrogen significantly accelerates the coupling of mechanical and physicochemical degradation, leading to multi-mechanism failure characterized by blistering, crack propagation, and modulus reduction. This review highlights the limitations of existing research, including insufficient long-term experimental data, simplified single-mechanism models, and the lack of multi-physics coupling analysis. Future research priorities are proposed in four aspects: (1) development of hydrogen blister-resistant elastomers, (2) collaborative optimization of sealing structures and materials, (3) in-depth investigation of tribological behavior under hydrogen cycling, and (4) establishment of predictive life models integrating multi-scale simulations and experimental validation. This work provides a state of the art of hydrogen-induced failure mechanisms and offers theoretical and engineering guidance for designing reliable sealing systems in next-generation hydrogen energy applications.

To address the brittle matrix failure frequently observed in filament-wound composite layers of onboard pressure vessels operating under cryogenic and high-pressure conditions, we studied a bisphenol-A epoxy resin (DGEBA) system modified with polyetheramine (T5000) and 3,4-Epoxycyclohexylmethyl 3′,4′-epoxycyclohexanecarboxylate (CY179). The curing and rheological behavior of the modified resin were first evaluated, revealing a favorable processing, with viscosity suitable for wet-filament winding. Subsequently, its coefficient of thermal expansion (CTE) and tensile properties were characterized over the 300 K–90 K range, demonstrating a linear increase in elastic modulus and tensile strength with decreasing temperature. Carbon fibre-reinforced polymer composites (CFRP) were then fabricated using this resin system, and both longitudinal and transverse tensile tests, along with microscopic fracture surface analyses, were conducted. The results showed that CFRP-0° specimens exhibited an initial increase followed by a decrease in elastic modulus with decreasing temperature, whereas CFRP-90° specimens demonstrated pronounced cryogenic strengthening, with tensile strength and modulus enhanced by 52.2% and 82.4%, respectively. The findings provide comprehensive properties for the studied resin system and its CFRP under room temperature (RT) to cryogenic conditions, offering a basis for the design and engineering of cryo-compressed hydrogen storage vessels.

This study investigates the co-pyrolysis behavior of two lignocellulosic biomass blends, bamboo (B), and rice straw (R) with a plastic polyethylene (P). A total of 15 samples, including binary and ternary blends, were analyzed. Firstly, X-ray diffraction (XRD) analysis was performed to reveal high crystallinity in the B25R75 blend (I/I_c = 13.39). Whereas, the polyethylene samples showed persistent ZrP₂O₇ and lazurite phases (I/I_c up to 3.12) attributed to additives introduced during the manufacturing of the commercial plastic feedstock. In addition, scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) spectroscopy was performed to characterize the surface morphology and elemental composition of the feedstock. Moreover, thermogravimetric analysis (TGA) was employed at temperatures up to 700 °C at three different heating rates (5, 10, and 20 °C/min) under pyrolysis conditions. Kinetic analysis used TGA data to calculate activation energy via Friedman’s isoconversional method, and the blended samples exhibited a decrease in activation energy compared to the individual components. Furthermore, the study evaluated transient interaction effects among the components by assessing the deviation between experimental and theoretical weight loss. This revealed the presence of significant synergistic behavior in certain binary and ternary blends. The results demonstrate that co-pyrolysis of bamboo and rice straw with polyethylene enhances thermal decomposition efficiency and provides a more favorable energy recovery route.