TY - JOUR A1 - Lamoriniere, S. A1 - Mitchell, P. J. A1 - Ho, K. A1 - Kalinka, Gerhard A1 - Shaffer, M. S. P. A1 - Bismarck, A. T1 - Carbon nanotube enhanced carbon Fibre-Poly(ether ether ketone) interfaces in model hierarchical composites N2 - Poly (ether ether ketone) (PEEK) has a high continuous service temperature, excellent mechanical properties, and good solvent and abrasion resistance, which can be further improved through the addition of carbon nanotubes (CNTs). CNT-PEEK nanocomposites are promising matrices for continuous carbon fibre composites; powder processing can mitigate the high melt viscosities in these systems. In this study, model single fibre (hierarchical) composites were produced by embedding sized and desized carbon fibres in nanocomposite CNTPEEK powders followed by single fibre pull-out tests to assess interfacial characteristics. Carbon fibre-PEEK interfacial shear strength is typically 40–45 MPa. Increasing CNT loadings increased fibre-matrix interfacial shear strength linearly up to ~70 MPa at 5.0 wt%, which was attributed to the CNT-based mechanical modification of the PEEK matrix. Apparent interfacial shear strength was inversely correlated with the embedded fibre length irrespective of carbon fibre sizing or CNT loading, indicating brittle fracture of the fibre-matrix interface. Pulled out carbon fibres were still coated with the matrix, which indicated strong adhesion at the interface in all samples, likely related to a transcrystalline region. Adhesion was, however, negatively affected by the presence of epoxy sizings. Frictional shear strength was independent of embedded fibre length and CNT content for all samples. KW - Keywords: Poly(ether ether ketone) KW - Carbon fibres KW - Carbon nanotubes KW - Interfacial strength KW - Debonding PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550052 DO - https://doi.org/10.1016/j.compscitech.2022.109327 SN - 0266-3538 VL - 221 SP - 1 EP - 8 PB - Elsevier Ltd. CY - Niederlande AN - OPUS4-55005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rodricks, Carol T1 - Advancing Sustainable Composites: Challenges and innovations N2 - With the increased use of carbon fibre polymer matrix composites comes the important question of their management at the end of their life cycle. Given the high costs associated with carbon fibre production, recycling carbon fibres from composite waste is a desirable source of reinforcing fibres for new applications. However, current recycling methods result in recycled carbon fibres that are short with little to no orientation which can only be used in applications requiring intermediate strength at a fraction of the potential of the continuous, aligned virgin fibres. Thus, a method to recycle fibres with their original length and orientation intact is vital to truly realising a circular economy for carbon fibre polymer composites. Our research introduces a novel hierarchical composite aimed at preserving the length and orientation of carbon fibres on recycling. Virgin carbon fibres are encapsulated in an insoluble epoxy matrix to form tapes that serve as the primary units of the hierarchical structure. The primary epoxy matrix protects the fibres from chemical and environmental elements while maintaining their permanent orientation. The primary tape units are subsequently embedded in a secondary recyclable matrix polymer to make larger composite structures. Elium, a thermoplastic that dissolves in acetone and has mechanical properties comparable to epoxy, was chosen as the secondary matrix of choice in this study. This approach aims to achieve a composite that is mechanical equivalent to thermoset composites while facilitating easy recycling with minimal impact on the fibres in the primary unit. T2 - Materials Week 2025 CY - Frankfurt am Main, Germany DA - 02.04.25 KW - Recycling KW - Carbon fibres KW - Mechanical testing KW - Polymer-matrix composites (PMCs), micromechanics KW - Elium PY - 2025 AN - OPUS4-63004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gebhardt, M. A1 - Manolakis, I. A1 - Chatterjee, A. A1 - Kalinka, Gerhard A1 - Deubener, J. A1 - Pfnür, H. A1 - Chakraborty, S. A1 - Meiners, D. T1 - Reducing the raw material usage for room temperature infusible and polymerisable thermoplastic CFRPs through reuse of recycled waste matrix material N2 - In this work, a closed loop recycling process is investigated, which allows polymerised bulk thermoplastic matrix (Elium 150) from production waste (also referred to as recyclate) to be reused as additive in composite manufacturing by vacuum assisted resin infusion (VARI) of virgin Elium 150 monomer. It is shown that this process can save up to 7.5 wt% of virgin material usage in each processing cycle. At the same time, the thermal stability and stiffness of the composite increases with the proportion of recyclate introduced. Contemporarily, the shear and bending properties have also been observed to improve. Gel permeation chromatography (GPC) showed that the changes observed are due to an increase in molecular weight with the recyclate content. In particular, a correlation between the molecular weight and the shear properties of the composite was discovered using single fibre push-out tests. KW - Mechanical properties KW - Recycling KW - Carbon fibres KW - Fibre/matrix bond PY - 2021 DO - https://doi.org/10.1016/j.compositesb.2021.108877 SN - 1359-8368 VL - 216 SP - 108877 PB - Elsevier Ltd. CY - Niederlande AN - OPUS4-52711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -