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The use of polypropylene (PP) waste in the textile industry has been limited to low-value applications, as it is difficult to produce high-quality recycled fibers. Recent advances in recycling and purification technologies have enabled the production of recycled polypropylene (rPP) suitable for textile-grade fibers. This study focuses on the melt spinning of rPP multifilament yarns obtained from post-consumer waste and evaluates the influence of critical spinning parameters such as godet temperature, quenching conditions, draw ratio and draw down speed on yarn properties. The test results show that highly purified rPP can be successfully spun into multifilament yarns with a tensile strength of up to 4.2 cN/dtex and an elongation at break of 20%. These values demonstrate the potential of using post-consumer PP in high-performance applications, overcoming the traditional limitations associated with recycled PP. This work provides a pathway for expanding the use of post-consumer waste in the production of high value textile fibers and promotes a more sustainable approach to polypropylene waste management.

Taking advantage of its high-temperature resistance and elongation properties, conductive-coated polyetheretherketone (PEEK) filament yarn can be used as a textile-based electroconductive functional element, in particular as a strain sensor. This study describes the development of electrical conductivity on an inert PEEK filament surface by the deposition of metallic nickel (Ni) layers via an electroless galvanic plating process. To enhance the adhesion properties of the nickel layer, both PEEK multifilament and monofilament yarn surfaces were metalized by plasma torch pretreatment, followed by nickel plating. Electrical characterizations indicate the potential of nickel-coated PEEK for structural monitoring in textile-reinforced composites. In addition, surface energy measurements before and after plasma torch pretreatment, surface morphology, nickel layer thickness, chemical structure changes, and mechanical properties were analyzed and compared with untreated PEEK. The thickness of the Ni layer was measured and showed an average thickness of 1.25 µm for the multifilament yarn and 3.36 µm for the monofilament yarn. FTIR analysis confirmed the presence of new functional groups on the PEEK surface after plasma torch pretreatment, indicating a successful modification of the surface chemistry. Mechanical testing showed an increase in tensile strength after plasma torch pretreatment but a decrease after nickel plating. In conclusion, this study successfully developed conductive PEEK yarns through plasma torch pretreatment and nickel plating.

Melt‐spun polypropylene/carbon nanotube (PP/CNT) monofilaments hold great promise for use in structural health monitoring (SHM) due to their low density, mechanical flexibility, and piezoresistive properties. However, achieving homogeneous CNT dispersion, optimizing processing parameters, and enhancing strain sensitivity remain key challenges for their practical implementation. This study systematically examines the influence of CNT and carbon black (CB) content as extrinsically conductive fillers, the incorporation of polyethylene glycol (PEG) as processing aids, and the effect of extruder screw speeds on the morphology, mechanical properties, and electrical behavior of PP/CNT monofilaments. Spinning pressure measurements reveal PEG effectively reduces spinning pressure. Morphological analysis indicates that higher CNT content results in rougher filament surfaces, while PEG enhances fiber uniformity. Tensile testing demonstrates a strong dependence of Young′s modulus and tensile strength on CNT content and processing parameters, with PEG‐modified samples exhibiting improved ductility. Electrical characterization confirmed a stable strain‐dependent resistance variation, with gauge factors up to 1.5. Mechanical testing showed that Young’s modulus could be tailored from 0.8 to 16 GPa depending on CNT and PEG content. These results demonstrate the feasibility of producing lightweight PP/CNT monofilaments with tunable electromechanical properties for scalable SHM sensor integration.

Thermoplastic polyurethane (TPU) is a unique polymer known for its excellent physical and chemical properties including exceptional elasticity and durability, excellent abrasion resistance and resistance to oil, water, acids and alkalis, making it indispensable in various industries. In recent years, growing environmental concerns have let to the development of bio-based thermoplastic polyurethane from renewable resources which provide a sustainable alternative to conventional fossil-based TPUs. This study investigates the melt spinning process of two types of TPU: Desmopan 385E, a conventional TPU, and Desmopan CQ33085AUEC, a partially bio-based TPU, focusing on their potential for high performance multifilament yarns. A comprehensive study evaluated their thermal, rheological and mechanical properties, as well as their processability at different drawdown ratios (DDR). Thermogravimetric analysis (TGA) revealed differences in decomposition temperatures and thermal stability while melt flow rate (MFR) testing optimized melt spinning parameters. Rheological measurements showed viscosity reductions of up to 90% after spinning, reflecting structural transformations such as chain alignment and scission, with implications for processing and yarn performance. Both TPU types were successfully processed into multifilament yarns under comparable spinning conditions, achieving process speeds of up to 2000 m/min. Mechanical tests revealed differences in tensile strength and elongation, with the bio-based TPU achieving mechanical properties comparable to or 7,4% better in tensile strength than those of its conventional counterpart, highlighting the potential of bio-based TPU as a sustainable alternative for technical textile applications.

A search for T and Y vector-like quarks produced in proton-proton collisions at a centre-of-mass energy of 13 TeV and decaying into Wb in the fully hadronic final state is presented. The search uses 139 fb(-1) of data collected by the ATLAS detector at the LHC from 2015 to 2018. The final state is characterised by a hadronically decaying W boson with large Lorentz boost and a b-tagged jet, which are used to reconstruct the invariant mass of the vector-like quark candidate. The main background is QCD multijet production, which is estimated using a data-driven method. Upon finding no significant excess in data, mass limits at 95% confidence level are obtained as a function of the global coupling parameter, kappa. The observed lower limits on the masses of Y quarks with kappa = 0.5 and kappa = 0.7 are 2.0 TeV and 2.4 TeV, respectively. For T quarks, the observed mass limits are 1.4 TeV for kappa = 0.5 and 1.9 TeV for kappa = 0.7.

This paper presents measurements of top-antitop quark pair (t (t) over bar) production in association with additional b-jets. The analysis utilises 140 fb(-1) of proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13TeV. Fiducial cross-sections are extracted in a final state featuring one electron and one muon, with at least three or four b-jets. Results are presented at the particle level for both integrated cross-sections and normalised differential cross-sections, as functions of global event properties, jet kinematics, and b-jet pair properties. Observable quantities characterising b-jets originating from the top quark decay and additional b-jets are also measured at the particle level, after correcting for detector effects. The measured integrated fiducial cross-sections are consistent with t (t) over barb (b) over bar predictions from various next-to-leading-order matrix element calculations matched to a parton shower within the uncertainties of the predictions. State-of-the-art theoretical predictions are compared with the differential measurements; none of them simultaneously describes all observables. Differences between any two predictions are smaller than the measurement uncertainties for most observables.

Differential cross-sections for top-quark pair production, inclusively and in association with jets, are measured in pp collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC using an integrated luminosity of 140 fb−1. The events are selected with one charged lepton (electron or muon) and at least four jets. The differential cross-sections are presented at particle level as functions of several jet observables, including angular correlations, jet transverse momenta and invariant masses of the jets in the final state, which characterise the kinematics and dynamics of the top-antitop system and the hard QCD radiation in the system with associated jets. The typical precision is 5%–15% for the absolute differential cross-sections and 2%–4% for the normalised differential cross-sections. Next-to-leading-order and next-to-next-to-leading-order QCD predictions are found to provide an adequate description of the rate and shape of the jet-angular observables. The description of the transverse momentum and invariant mass observables is improved when next-to-next-to-leading-order QCD corrections are included.

Three searches for the direct production of tau-sleptons or charginos and neutralinos in final states with at least two hadronically decaying tau-leptons are presented. For chargino and neutralino production, decays via intermediate tau-sleptons or W and h bosons are considered. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of 139 fb(-1), recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13TeV. No significant deviation from the expected Standard Model background is observed and supersymmetric particle mass limits at 95% confidence level are obtained in simplified models. For direct production of (X) over tilde +/-(1) (X) over tilde -1, chargino masses are excluded up to 970 GeV, while (X) over tilde +/-(1) 1 and (X) over tilde (0)2 masses up to 1160 GeV (330 GeV) are excluded for (X) over tildeC(+/-) (1) (X) over tilde (0)(2) /(X) over tilde (+)(1) (X) over tilde -1 production with subsequent decays via t -sleptons ( W and h bosons). Masses of tau-sleptons up to 500 GeV are excluded for mass degenerate (tau) over tildeL, R scenarios and up to 425 GeV for (tau) over tilde (L) -only scenarios. Sensitivity to (tau) over tilde (R) -only scenarios from the ATLAS experiment is presented here for the first time, with (tau) over tilde (R) masses excluded up to 350 GeV.

A search for a heavy CP-odd Higgs boson, A, decaying into a Z boson and a heavy CP-even Higgs boson, H, is presented. It uses the full LHC Run 2 dataset of pp collisions at s = 13 TeV collected with the ATLAS detector, corresponding to an integrated luminosity of 140 fb−1. The search for A → ZH is performed in the ℓ+ℓ−tt¯ and νν¯bb¯ final states and surpasses the reach of previous searches in different final states in the region with mH > 350 GeV and mA > 800 GeV. No significant deviation from the Standard Model expectation is found. Upper limits are placed on the production cross-section times the decay branching ratios. Limits with less model dependence are also presented as functions of the reconstructed m(tt¯) and m(bb¯) distributions in the ℓ+ℓ−tt¯ and νν¯bb¯ channels, respectively. In addition, the results are interpreted in the context of two-Higgs-doublet models.

This paper reports a search for a light CP-odd scalar resonance with a mass of 20 GeV to 90 GeV in 13TeV proton-proton collision data with an integrated luminosity of 140 fb(-1) collected with the ATLAS detector at the Large Hadron Collider. The analysis assumes the resonance is produced via gluon-gluon fusion and decays into a tau(+)tau(-) pair which subsequently decays into a fully leptonic mu(+)nu(mu)(nu) over bar (tau)e(-)(nu) over bar (e)nu(tau) or e(+)nu(e)(nu) over bar (tau)mu(-)(nu) over bar (mu)nu(tau) final state. No significant excess of events above the predicted Standard Model background is observed. The results are interpreted within a flavour-aligned two-Higgs-doublet model, and a model-independent cross-section interpretation is also given. Upper limits at 95% confidence level between 3.0 pb and 68 pb are set on the cross-section for producing a CP-odd Higgs boson that decays into a tau(+)tau(-) pair.