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1 – 6 of 6Marialuigia Raimondo, Felice De Nicola, Ruggero Volponi, Wolfgang Binder, Philipp Michael, Salvatore Russo and Liberata Guadagno
The purpose of this paper is to describe the first experiments to manufacture self-healing carbon fiber reinforced panels (CFRPs) for the realization of structural aeronautic…
Abstract
Purpose
The purpose of this paper is to describe the first experiments to manufacture self-healing carbon fiber reinforced panels (CFRPs) for the realization of structural aeronautic components in order to address their vulnerability to impact damage in the real service conditions.
Design/methodology/approach
The developed self-healing system is based on ring-opening metathesis polymerizations reaction of microencapsulated 5-ethylidene-2-norbornene/dicyclopentadiene cyclic olefins using Hoveyda-Grubbs’ first generation catalyst as initiator. In this work, the self-healing resin is infused into a carbon fiber dry preform using an unconventional bulk film infusion technique that has allowed to minimize the filtration effects via a better compaction and reduced resin flow paths. Infrared spectroscopy provides a useful way to identify metathesis products and therefore catalyst activity in the self-healing panel after damage. The damage resistance of the manufactured CFRPs is evaluated through hail and drop tests.
Findings
The self-healing manufactured panels show, after damage, catalyst activity with metathesis product formation, as evidenced by an infrared peak at 966 cm−1. The damage response of CFRPs, detected in accord to the requirements of hail impact for the design of a fuselage in composite material, is very good. The results are very encouraging and can constitute a solid basis for bringing this new technology to the self-healable fiber reinforced resins for aerospace applications.
Originality/value
In this paper, autonomically healing CFRPs with damage resistance and self-healing function are proposed. In the development of self-healing aeronautic materials it is critical that self-healing activity functions in adverse weather conditions and at low working temperatures which can reach values as low as −50°C.
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Elisa Calabrese, Pasquale Longo, Carlo Naddeo, Annaluisa Mariconda, Luigi Vertuccio, Marialuigia Raimondo and Liberata Guadagno
The purpose of this paper is to highlight the relevant role of the stereochemistry of two Ruthenium catalysts on the self-healing efficiency of aeronautical resins.
Abstract
Purpose
The purpose of this paper is to highlight the relevant role of the stereochemistry of two Ruthenium catalysts on the self-healing efficiency of aeronautical resins.
Design/methodology/approach
Here, a very detailed evaluation on the stereochemistry of two new ruthenium catalysts evidences the crucial role of the spatial orientation of phenyl groups in the N-heterocyclic carbene ligands in determining the temperature range within the curing cycles is feasible without deactivating the self-healing mechanisms (ring-opening metathesis polymerization reactions) inside the thermosetting resin. The exceptional activity and thermal stability of the HG2MesPhSyn catalyst, with the syn orientation of phenyl groups, highlight the relevant potentiality and the future perspectives of this complex for the activation of the self-healing function in aeronautical resins.
Findings
The HG2MesPhSyn complex, with the syn orientation of the phenyl groups, is able to activate metathesis reactions within the highly reactive environment of the epoxy thermosetting resins, cured up to 180°C, while the other stereoisomer, with the anti-orientation of the phenyl groups, does not preserve its catalytic activity in these conditions.
Originality/value
In this paper, a comparison between the self-healing functionality of two catalytic systems has been performed, using metathesis tests and FTIR spectroscopy. In the field of the design of catalytic systems for self-healing structural materials, a very relevant result has been found: a slight difference in the molecular stereochemistry plays a key role in the development of self-healing materials for aeronautical and aerospace applications.
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Panagiota Polydoropoulou, Christos Vasilios Katsiropoulos, Andreas Loukopoulos and Spiros Pantelakis
Over the last decades, self-healing materials based on polymers are attracting increasing interest due to their potential for detecting and “autonomically” healing damage. The use…
Abstract
Purpose
Over the last decades, self-healing materials based on polymers are attracting increasing interest due to their potential for detecting and “autonomically” healing damage. The use of embedded self-healing microcapsules represents one of the most popular self-healing concepts. Yet, extensive investigations are still needed to convince on the efficiency of the above concept. The paper aims to discuss these issues.
Design/methodology/approach
In the present work, the effect of embedded self-healing microcapsules on the ILSS behavior of carbon fiber reinforced composite materials has been studied. Moreover, the self-healing efficiency has been assessed. The results of the mechanical tests were discussed supported by scanning electron microscope (SEM) as well as by Attenuated Total Reflection–Fourier-transform infrared spectroscopy (ATR–FTIR) analyses.
Findings
The results indicate a general trend of a degraded mechanical behavior of the enhanced materials, as the microcapsules exhibit a non-uniform dispersion and form agglomerations which act as internal defects. A remarkable value of the self-healing efficiency has been found for materials with limited damage, e.g. matrix micro-cracks. However, for significant damage, in terms of large matrix cracks and delaminations as well as fiber breakages, the self-healing efficiency is limited.
Originality/value
The results obtained by SEM analysis as well as by ATR–FTIR spectroscopy constitute a strong indication that the self-healing mechanism has been activated. However, further investigation should be conducted in order to provide definite evidence.
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Megavannan Mani, Thiyagu Murgaiyan and Pradeep Kumar Krishnan
This study focuses on the structural performance assessment of hybrid polymer composites for pick-and-place robot grippers used in critical infrastructure. This research involved…
Abstract
Purpose
This study focuses on the structural performance assessment of hybrid polymer composites for pick-and-place robot grippers used in critical infrastructure. This research involved the creation of composite materials with different nanoparticle concentrations, followed by extensive testing to assess the mechanical properties of the materials, such as strength, stiffness and durability.
Design/methodology/approach
The composites comprised bidirectional interply inclined carbon fibers (C), S-glass fibers (SG), E-glass (EG), an epoxy matrix and silica nanoparticles (SNiPs). During construction, the composite materials must be carefully layered using quasi-static sequence techniques (45°C1/45°SG2/45°EG2/45°C1/45°EG2/45°SG2/45°C1) to obtain the epoxy matrix reinforcement and bonding using 0, 2, 4 and 6 wt. % of silica nanoparticles.
Findings
According to various test findings, the 4 wt. % of SNiPs added to polymer plates exhibits the maximum strength outcomes. The average results of the tensile and flexural tests for the polymer composite plates with 4 wt. % addition SNiPs were 127.103 MPa and 223.145 MPa, respectively. The average results of the tensile and flexural tests for the plates with 0 wt.% SNiPs were 115.457 MPa and 207.316 MPa, respectively.
Originality/value
The authors hereby attest that the research paper they have submitted is the result of their own independent and unique labor. All of the sources from which the thoughts and passages were derived have been properly credited. The work has not been submitted for publication anywhere and is devoid of any instances of plagiarism.
Highlights
The study enhances the engineering materials for innovative applications.
The study explores the mechanical behavior of carbon/S-glass/E-glass fiber composites.
Silica nanoparticles were enhancing mechanical characteristics of the composite structure.
The study enhances the engineering materials for innovative applications.
The study explores the mechanical behavior of carbon/S-glass/E-glass fiber composites.
Silica nanoparticles were enhancing mechanical characteristics of the composite structure.
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Abstract
Purpose
The purpose of this paper is to synthesise and characterise novel thermally expandable microcapsules having poly (acrylonitrile (AN)‐methyl methacrylate (MMA)‐butyl acrylate (BA)) copolymer shells and p‐toluenesulphonylhydrazide (TSH) cores.
Design/methodology/approach
The novel thermally expandable microcapsules are synthesised by suspension polymerisation. The effects of various parameters including monomers and surfactant compositions on thermal expandability and stability, and particle size and size distributions of the microcapsules obtained are studied. Fourier transform infrared (FTIR) and scanning electronic microscopy (SEM) analyses are employed to characterise the chemical structure and morphology of the microcapsules obtained.
Findings
Suspension polymerisation with the monomers composition of 70 per cent AN/20 per cent MMA/10 per cent BA can yield microcapsules having a good expansion property and heat stability at 150°C. The paper also finds that when the amount of the incorporated PA reaches 20 per cent, the shells of microcapsules obtained will adhere together and some shells rupture resulting in the collapse of many of the expanded microcapsules. During the course of polymerisation, high‐molecular surfactant styrene – maleic acid copolymer sodium salt can help to achieve microcapsules with more uniform size distribution. FTIR and SEM characterisation show that the chemical structure of microcapsules contain core material and copolymeric shell and the morphology of microcapsules is very well defined, core‐shell type, respectively.
Research limitations/implications
The shell copolymer in the present context is synthesised from acrylonitrile‐methyl methacrylate‐ and butyl acrylate. Besides, it can be synthesised from other monomers also. In addition, the expansion efficiency of microcapsules can be studied.
Practical implications
The learning gained through this paper can be applied to the synthesis and application of other microcapsule or even nano‐capsule systems.
Originality/value
The method for preparation of TSH microcapsules by suspension polymerisation is novel and the microcapsules could find applications in water‐based intumescent and flame retardant wood coatings.
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