Rodrigue Matadi Boumbimba

Graphene has emerged as a promising nanofiller for the development of multifunctional polymer nanocomposites due to its outstanding mechanical, thermal, and electrical properties. In this study, Elium acrylic/Few‐Layer Graphene (FLG) nanocomposites were developed by incorporating low FLG contents (0.01–0.4 wt.%) into a liquid thermoplastic acrylic resin. Transmission electron microscopy (TEM) was used to qualitatively assess the morphology and dispersion state of FLG within the matrix. The nanocomposites were then characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and tensile testing. The results show that low FLG contents lead to a relatively homogeneous dispersion, whereas higher loadings promote the formation of localized aggregates. Thermal and mechanical analyses revealed improvements in glass transition temperature, tensile strength, and strain‐rate sensitivity, which can be attributed to a combination of effective filler–matrix interactions and possible modifications in polymer chain mobility. Overall, these results demonstrate that low FLG loadings can effectively enhance the thermomechanical performance of Elium‐based nanocomposites, highlighting their potential for lightweight and multifunctional structural applications.

This study investigated the viscoelastic behavior of unidirectional flax fibers/Elium acrylic composite reinforced with multiwall carbon nanotubes (MWCNT), focusing on their sensitivity to strain rate and temperature. In parallel, a cyclic tensile analysis was performed to monitor damage mechanisms in the composite. The results revealed enhanced mechanical and viscoelastic properties with increasing load and frequency. However, a reduction of 7°C in the relaxation associated to the glass transition temperature (T_g) was observed, as measured by dynamic mechanical analysis, in composites containing MWCNT. The study also highlighted the strain rate and temperature dependence of the flax fibers/Elium acrylic composite. Damage analysis revealed that the inclusion of MWCNTs delayed the onset of damage in the composite, suggesting that MWCNTs enhance material strength and improve durability. Additionally, a new model, combining Richeton's approach with numerical modeling, showed good agreement with experimental data.Highlights: MWCNTs improved fiber‐matrix interface in flax/Elium composites. Strain rate sensitivity, even with MWCNTs. MWCNTs raised storage modulus and shifted T_g to lower temperatures. MWCNTs delayed damage, enhancing composite durability. The new model provides a good prediction of elastic modulus.

This study evaluated the effect of multi‐walled carbon nanotubes (MWCNT) addition on the thermomechanical, and electrical responses of unidirectional flax fibers/Elium acrylic modified carbon nanotubes‐based composite. The manufacturing process of these laminated composites involved infusing the nanofillers onto the fibers, ensuring good dispersion of MWCNT within the matrix. Regardless of the rate of incorporated nanotubes, this study revealed a significant deterioration of the mechanical properties in tension and viscoelastic properties of the Elium acrylic resin‐based nanocomposite. The electrical conductivity significantly increased for all nanocomposites and laminated composites. In contrast to the nanocomposite, the unidirectional flax fibers/MWCNT/Elium acrylic composite exhibited a considerable improvement in mechanical properties. An increase in Young's modulus and stress at break of about 27% and 23% respectively, was achieved for the material loaded with 2 wt% of MWCNT. The presence of MWCNT reduces the saturation weight by 5% for the unidirectional composite filled with an amount of 1.5 wt% in MWCNT.Highlights: Improving the electrical properties of nanocomposites and unidirectional fibers (UD) composites. Improving the mechanical properties of Elium/flax/multi‐walled carbon nanotubes (MWCNT) composites. Influence of MWCNTs on the water absorption of UD composites. Influence of MWCNT on the glass transition temperature of nanocomposites. Inhibiting polymerization of MWCNT with Elium.

Elium® Acrylic/Glass Fiber thermoplastic laminate composites are liable to develop irreversible local defects under quasi‐static loading. To reinforce the damaged material, repair is a cost‐effective mechanical alternative. The present study investigates the tensile behavior of an Elium® glass‐fiber‐based acrylic laminate composite panel, repaired by vacuum bonding with Elium® repair resin and double overlap of external patches (DP). The results obtained for all repaired laminate composites E190/GF_D(10, 20, 30)R with diameters 10, 20, and 30 mm showed an improvement in the mechanical properties of the repaired panels, compared with the drilled and pristine samples. Average load recovery rates were significant for E190/GF_D10R (7.9%, 3.55%, 13%) E190/GF_D20R (23%, 18%, 3.32%), E190/GF_D30R (7.2%, 9.36%, 32.37%) at strain rates of 0.001, 0.01, and 0.05 s⁻¹ respectively. Finite element (FE) models for the virgin, drilled, and repaired composite, performed by coupling the Hashin criteria with the cohesive zone model (CZM), provided a relevant prediction of intra‐ and interlaminar failures of these woven laminated composites.Highlights: The effect of vacuum bonding repair with Elium E351 EOT resin was studied. Symmetrical repair of acrylic laminate drilled by fiberglass patches. Tensile strength of the repaired laminates was investigated. Intra‐ and interlaminar damage was predicted by finite elements modeling.

Impact resistance is one of the most critical features of composite structures, and therefore, its examination for a new material has a fundamental importance. This paper is devoted to the characterization of the fully recyclable thermoplastic ELIUM acrylic resin reinforced by glass fabric woven, which belongs to a new category of materials requiring advanced testing before their application in responsible elements of engineering structures. Its high strength, low weight as well as low production cost give excellent opportunities for its wide application in the automotive industry as a replacement of the thermoset-based laminates. The study presents an experimental work concerning the effect of damage due to low and high cyclic fatigue aging of two groups of specimens, first with the woven fabric orientations of [0°/90°]₄ and secondly with [45°/45°]₄, on the low impact velocity properties. The impact resistance was measured in terms of load peak, absorbed energy, penetration threshold and damage analysis. The low velocity impact results indicate that the uniaxial cyclic loading (fatigue aging) of the material leads to the reduction of impact resistance, especially at the high impact energy levels. Scanning Electron Microscopy (SEM) and Computed Tomography (CT) scan observations reveal that the damage area grows with the increase of both strain amplitude and impact energy.

The effect of reprocessing on the quasi-static uniaxial tensile behavior of two commercial polypropylene (PP)-based composites is experimentally investigated and modeled. In particular, the studied materials consist of an unfilled high-impact PP and a talc-filled high-impact PP. These PP composites are subjected to repeated processing cycles, including a grinding step and an extrusion step to simulate recycling at the laboratory level, the selected reprocessing numbers for this study being 0, 3, 6, 9, and 12. Because the repeated reprocessing leads to thermo-mechanical degradation by chain scission mechanisms, the tensile behavior of the two materials exhibits a continuous decrease of elastic modulus and failure strain with the increasing amount of reprocessing. A physically consistent three-dimensional constitutive model is used to predict the tensile response of non-recycled materials with strain rate dependence. For the recycled materials, the reprocessing effect is accounted by incorporating the reprocessing sensitive coefficient into the constitutive model for Young’s modulus, failure strain, softening, and hardening equations. Our predictions of true stress—true strain curves for non-recycled and recycled 108MF97 and 7510—are in good agreement with experimental data and can be useful for industries and companies which are looking for a model able to predict the recycling effect on mechanical behavior of polymer-based materials.