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This study explores the enhancement of Carbon Fibre Reinforced Polymers (CFRPs) for automotive applications through the integration of modified carbon fibres (CF) and epoxy matrices. The research emphasizes the use of block copolymers (BCPs) and electropolymerisation techniques to improve mechanical properties and interfacial adhesion. Incorporating 2.5 wt.% D51N BCPs in the epoxy matrix led to a 64% increase in tensile strength and a 51.4% improvement in interlaminar fracture toughness. The electropolymerisation of CFs further enhanced interlaminar shear strength by 23.2%, reflecting a substantial enhancement in fibre–matrix interaction. A novel out-of-autoclave manufacturing process for an energy absorber prototype was developed, achieving significant reductions in production time and cost while maintaining performance. Compression tests demonstrated that the modified materials attained an energy absorption rate of 93.3 J/mm, comparable to traditional materials. These results suggest that the advanced materials and manufacturing processes presented in this study are promising for the development of lightweight, high-strength automotive components, meeting rigorous performance and safety standards. This research highlights the potential of these innovations to contribute significantly to the advancement of materials used in the automotive industry. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate a novel exploitation approach for a mass livestock byproduct, namely sheep wool fibres. In order to fulfil this aim, wool fibre toughened epoxy composites with an amount of 2.4, 4.1 and 5.7 phr were prepared via the hot press method. Initially, mechanical assessment of the composites was executed, in order to evaluate their mechanical integrity. The flexural and shear strength tests showed that the wool fibre-epoxy composites maintain their mechanical properties for up to 4.1 phr and no degradation is detected. Subsequently, the thermal properties were tested. Thermogravimetric analysis proved that adding wool fibres as toughening agent in epoxy matrix can prolong the endurance of the material while reaching high temperatures. The coefficient of thermal conductivity decreased by 30% compared to neat epoxy, something that is also confirmed through simulation, proving that wool fibre-epoxy composites can be considered as a promising insulating material, while exploiting a natural waste. [ABSTRACT FROM AUTHOR]

Abstract In the present study the enhancement of fibre-matrix interfacial strength in carbon fibre composites was investigated via the electro-polymerization of poly methacrylic acid on commercially available carbon fibre fabrics. The surface modification of the fabrics was examined by means of Infrared (IR) and X-Ray photoelectron (XPS) spectroscopy whereas the surface morphology was studied via Scanning Electron Microscopy (SEM) and Atomic Force Microscopy(AFM). The wetting properties of the modified carbon fibres were investigated via contact angle measurements in single fibre and bundle specimens. For the mechanical performance assessment carbon fibre reinforced polymers (CFRPs) were prepared, via the vacuum resin infusion technique, using both modified and pristine fabrics and subsequently tested via macro scale mechanical testing. All modified composite specimens exhibited increased mechanical performance whereas the most optimum result was reported in Interlaminar Shear Strength (ILSS). [ABSTRACT FROM AUTHOR]

• Combination of 2D and 3D techniques for CFRPs' integrity analysis and heal ability. • Surface restoration on micro composites from artificial scratch through SEM analysis. • Recovery rate up to 50% on damaged CFRP reinforced by SH-capsules through DCB test. • Isolation and study of crack by advanced functions of m-CT. In the present study, the healing efficiency of microcapsules containing dicyclopentadiene (DCDP) was investigated on carbon fibre reinforced polymers (CFRPs) via morphological and mechanical characterisation. Micro-computed tomography (m-CT) has been used to observe in three dimensions (3D) the dynamic process of crack propagation and give CFRPs qualitative and quantitative structural and compositional information. Microcapsules with Poly(urea-formaldehyde) as shell and DCPD as healing agent in core were prepared by in situ polymerization in an oil-in-water emulsion. The morphology and thermal properties of microcapsules were examined via Optical Microscopy, Scanning Electron Microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Vacuum bagging was proved an efficient technique for the CFRPs' manufacturing that microcapsules can endure. The morphology of heal progression of cracks, induced at the surface of microplastics, was observed through SEM, while for the mechanical response double cantilever beam (DCB) test was selected to evaluate heal efficiency. The reduction of the crack volume in the CFRPs internal structures was up to 45%, while the mechanical restoration exceeded 50% proving microcapsules' efficiency. [ABSTRACT FROM AUTHOR]

During Carbon Fibre Reinforced Polymers (CFRPs) manufacturing, large quantities of scrap are being produced and usually disposed to landfill or incinerated, resulting in a high environmental impact. Furthermore, CFRP parts that have been damaged or reached their end-of-life, follow the same disposal route and because of this, not only the environment is affected, but also high added-value materials, such as carbon fibres (CFs) are lost without further valorisation. Several recycling technologies have been suggested, such as pyrolysis, to retrieve the CF reinforcement from the CFRPs. However, pyrolysis produces CFs that have residual resin and pyrolytic carbon at their surface. In order to retrieve clean long fibres, oxidation treatment in high temperatures is required. The oxidation treatment, however, has a high impact on the mechanical properties of the reclaimed CFs; therefore, an optimised pyrolysis procedure of CFRPs and post-pyrolysis treatment of reclaimed fibres (rCFs) is required. In this study, CFRPs have been subjected to pyrolysis to investigate the reclamation of CF fabrics in their primal form. The temperature of 550 °C was selected as the optimum processing temperature for the investigated composites. A parametric study on the post-pyrolysis treatment was performed in order to remove the residues from the fabrics and at the same time to investigate the CFs reusability, in terms of their mechanical and surface properties. [ABSTRACT FROM AUTHOR]

The present study focuses on the effect of two novel carbon fibre surface treatments, electropolymerisation of methacrylic acid and air pressure plasma, on the mechanical properties and structural integrity of carbon-fibre-reinforced composites under operational conditions. Extensive mechanical testing was applied, both in nano- and macro-scale, to assess the performance of the composites and the interphase properties after ultraviolet/humidity weathering. The results of the mechanical assessment are supported by structure, surface, and chemistry examination in order to reveal the failure mechanism of the composites. Composites with the electropolymerisation treatment exhibited an increase of 11.8% in interlaminar shear strength, while APP treatment improved the property of 23.9%, rendering both surface treatments effective in increasing the fibre-matrix adhesion. Finally, it was proven that the developed composites can withstand operational conditions in the long term, rendering them suitable for a wide variety of structural and engineering applications. [ABSTRACT FROM AUTHOR]

The exposure of carbon-fiber-reinforced polymers (CFRPs) to open-field conditions was investigated. Establishment of structure–property relations with nanoindentation enabled the observation of modification effects on carbon-fiber interfaces, and impact resistance. Mapping of nanomechanical properties was performed using expectation-maximization optimization of Gaussian fitting for each CFRPs microstructure (matrix, interface, carbon fiber), while Weibull analysis connected the weathering effect to the statistically representative behavior of the produced composites. Plasma modification demonstrated reduced defect density and improved nanomechanical properties after weathering. Artificial intelligence for anomaly detection provided insights on condition monitoring of CFRPs. Deep-learning neural networks with three hidden layers were used to model the resistance to plastic deformation based on nanoindentation parameters. This study provides new assessment insights in composite engineering and quality assurance, especially during exposure under service conditions. [ABSTRACT FROM AUTHOR]

Carbon Fibres (CFs) are widely used in textile-reinforced composites for the construction of lightweight, durable structures. Since their inert surface does not allow effective bonding with the matrix material, the surface treatment of fibres is suggested to improve the adhesion between the two. In the present study, different surface modifications are compared in terms of the mechanical enhancement that they can offer to the fibres. Two main advanced technologies have been investigated; namely, plasma treatment and electrochemical treatment. Specifically, active screen plasma and low-pressure plasma were compared. Regarding the electrochemical modification, electrochemical oxidation and electropolymerisation of monomer solutions of acrylic and methacrylic acids, acrylonitrile and N-vinyl pyrrolidine were tested for HTA-40 CFs. In order to assess the effects of the surface treatments, the morphology, the physicochemical properties, as well as the mechanical integrity of the fibres were investigated. The CF surface and polymeric matrix interphase adhesion in composites were also analysed. The improvement of the carbon fibre's physical–mechanical properties was evident for the case of the active screen plasma treatment and the electrochemical oxidation. [ABSTRACT FROM AUTHOR]

Advanced active screen plasma (ASP) technology is used to modify polyacrylonitrile‐derived carbon fibre (CF) surfaces using gas mixtures of N2–H2 and N2–H2–Ar. Unlike conventional plasma treatments, ASP treatment can reduce the structural disorder of CF surfaces and increase the surface crystallite size. Moreover, ASP treatment can lead to an increased single fibre tensile strength. This is mainly because the post‐plasma nature of the ASP technology can effectively eliminate ion‐bombardment‐induced degradation while providing radicals necessary for surface modification. The addition of argon to the nitrogen–hydrogen gas mixture contributes to a more ordered graphitic structure on CF surfaces and further increases the single fibre tensile strength. The interfacial properties (interlaminar shear strength and flexural strength) of the resulting composites are improved. [ABSTRACT FROM AUTHOR]

A polyamide (PA) 12-based thermoplastic composite was modified with carbon nanotubes (CNTs), CNTs grafted onto chopped carbon fibers (CFs), and graphene nanoplatelets (GNPs) with CNTs to improve its thermal conductivity for application as a heat sink in electronic components. The carbon-based nanofillers were examined by SEM and Raman. The laser flash method was used to measure the thermal diffusivity in order to calculate the thermal conductivity. Electrical conductivity measurements were made using a Keithley 6517B electrometer in the 2-point mode. The composite structure was examined by SEM and micro-CT. PA12 with 15 wt% of GNPs and 1 wt% CNTs demonstrated the highest thermal conductivity, and its processability was investigated, utilizing sequential interdependence tests to evaluate the composite material behavior during fused filament fabrication (FFF) 3D printing processing. Through this assessment, selected printing parameters were investigated to determine the optimum parametric combination and processability window for the composite material, revealing that the selected composition meets the necessary criteria to be processable with FFF. [ABSTRACT FROM AUTHOR]

Life cycle assessment is a methodology to assess environmental impacts associated with a product or system/process by accounting resource requirements and emissions over its life cycle. The life cycle consists of four stages: material production, manufacturing, use, and end-of-life. This study highlights the need to conduct life cycle assessment (LCA) early in the new product development process, as a means to assess and evaluate the environmental impacts of (nano)enhanced carbon fibre-reinforced polymer (CFRP) prototypes over their entire life cycle. These prototypes, namely SleekFast sailing boat and handbrake lever, were manufactured by functionalized carbon fibre fabric and modified epoxy resin with multi-walled carbon nanotubes (MWCNTs). The environmental impacts of both have been assessed via LCA with a functional unit of '1 product piece'. Climate change has been selected as the key impact indicator for hotspot identification (kg CO2 eq). Significant focus has been given to the end-of-life phase by assessing different recycling scenarios. In addition, the respective life cycle inventories (LCIs) are provided, enabling the identification of resource hot spots and quantifying the environmental benefits of end-of-life options. [ABSTRACT FROM AUTHOR]