Alternative Concepts for Extruded Power Cable Insulation: from Thermosets to Thermoplastics
Amir Masoud Pourrahimi, Massimiliano Mauri, Silvia D'Auria, Roberta Pinalli, Christian Müller
Published online: 12 April 2024
The most common type of insulation of extruded high-voltage power cables is composed of low-density polyethylene (LDPE), which must be crosslinked to adjust its thermomechanical properties. A major drawback is the need for hazardous curing agents and the release of harmful curing byproducts during cable production, while the thermoset nature complicates reprocessing of the insulation material. This perspective explores recent progress in the development of alternative concepts that allow to avoid byproducts through either click chemistry type curing of polyethylene-based copolymers or the use of polyolefin blends or copolymers, which entirely removes the need for crosslinking. Moreover, polypropylene-based thermoplastic formulations enable the design of insulation materials that can withstand higher cable operating temperatures and facilitate reprocessing by remelting once the cable reaches the end of its lifetime. Finally, polyethylene-based covalent and non-covalent adaptable networks are explored, which may allow to combine the advantages of thermoset and thermoplastic insulation materials in terms of thermomechanical properties and reprocessability.
Polyethylene ionomers as thermally reversible and aging resilient adhesives
Silvia D'Auria, Peter Neuteboom, Roberta Pinalli, Enrico Dalcanale, Jérôme Vachon
Published online: 03 April 2024
In this work, we report the effect of the reaction conditions on IPC content and melt flow index (MFI) for the PE ionomer obtained by copolymerizing ethylene with the ion pair dimethyl-amino methacrylate and methacrylic acid. The resulting ionomers exhibited improved mechanical properties, including higher elongation and stress at break, making them superior to conventional LDPE. The developed ionomers display enhanced adhesion properties on aluminum substrates with respect to LDPE. Remarkably, the adhesives exhibit thermal reversibility, making them suitable for applications requiring disassembly. Accelerated aging tests demonstrate the ionomers’ durability, with some even showing increased adhesion after exposure to harsh conditions. Overall, this study highlights the potential of PE-based ionomers as advanced materials that combine the benefits of thermosets and thermoplastics, while offering outstanding adhesive properties when the IPC content is higher than 1 mol %.
Synthesis and
Processing of Near Infrared—Activated Vitrimer Nanocomposite Films
Modified with β-Hydroxyester-Functionalized Multi-Walled Carbon
Nanotubes
Synthesis and Processing of Near Infrared—Activated Vitrimer Nanocomposite Films Modified with β-Hydroxyester-Functionalized Multi-Walled Carbon Nanotubes
Tomás E. Byrne Prudente, Diandra Mauro, Julieta Puig, Facundo I. Altuna, Tatiana Da Ros and Cristina E. Hoppe
Published online: 08 December 2023
Films of a vitrimer based on the reaction between diglycidylether of bisphenol A and glutaric acid in the presence of 1-methylimidazole were processed using a solvent-based technique. The curing schedule was divided into two steps: first, a soluble linear polymer was formed through the reaction of the diacid and the diepoxide, and then the crosslinking was induced at a higher temperature via transesterification reactions. This epoxy–acid vitrimer was modified with multi-walled carbon nanotubes (MWCNTs) functionalized with β-hydroxyesters, produced by a robust and straightforward strategy based on a two-phase reaction between oxidized MWCNTs and phenylglycidylether. Nanocomposite vitrimer films were obtained by drop casting a dispersion of the functionalized MWCNTs in the linear polymer/cyclohexanone solution, followed by a thermal treatment. A high degree of dispersion of the carbon nanostructures was attained thanks to the β-hydroxyester functionalization when compared with oxidized MWCNTs. Nanocomposite films showed a significant photothermal effect (reaching 200 °C or above in 30 s) upon NIR light irradiation (850 nm) from a single LED (500 mW/cm2). The released heat was used to activate the shape memory effect and weld and heal the vitrimer matrix, proving the success of this easy strategy for the generation of remotely activated carbon-based vitrimer nanocomposites.
CIE color coordinates for the design of luminescent glass materials
CIE color coordinates for the design of luminescent glass materials
Andreia Ruivo and César Laia
Published online: 08 November 2023
In this study, a soda-lime silicate glass composition was doped with a mixture of different lanthanide oxides to increase the luminescence color palette. The same glass sample can also present different colors by changing the excitation light, allowing higher tunability of luminescent colors. It was effectively demonstrated the extensive spectrum of colors produced, which was represented through luminescence color coordinates for all synthesized glasses. Moreover, the possibility of detecting if an excited state process is occurring was studied by calculating the lanthanides factors and comparing them with those used in the glass synthesis. Nevertheless, it is shown that the energy transfer process has to be significant to influence the color coordinates and the calculation of the factors.
Photoreduction of Anthracenes Catalyzed by peri-
Xanthenoxanthene: a Scalable and Sustainable Birch-Type
Alternative
Cristian De Luca, Davide Zanetti, Tommaso Battisti, Rúben R. Ferreira, Sofia Lopez, Alexander H. McMillan, Sasha Cai Lesher-Pérez, Laura Maggini, and Davide Bonifazi
Published online: 18 August 2023
Photocatalyzed “Birch-type” reduction of acenes by using peri-xanthenoxanthene (PXX). This work presents a novel method for reducing various full-carbon acenes using visible blue light and PXX as a photocatalyst. By attaching PXX to PDMS beads, catalyst recyclability can be achieved without compromising efficiency. Integration of the PXX-PDMS beads into a microreactor enabled the reduction of acenes under continuous-flow conditions, thereby validating the sustainability and scalability of this heterogeneous-phase approach.
Phenoxy Resin-Based Vinylogous Urethane Covalent Adaptable Networks
Giuseppe Soavi, Francesca Portone, Daniele Battegazzore, Chiara Paravidino, Rossella Arrigo, Alessandro Pedrini, Roberta Pinalli, Alberto Fina, Enrico Dalcanale
Published online: 30 July 2023
This work presents a post-polymerization approach to the preparation of vitrimers, exploiting the transamination of vinylogous urethane in linear phenoxy resins. The conversion of linear polymers to dynamic crosslinked networks is confirmed by dynamic mechanical thermal analyzer and rheology measurements, followed by stress relaxation tests to investigate the kinetics of bond exchanges. Tensile tests as a function of reprocessing cycles reveal an increase of the maximum elongation and stress at break and prove the good recyclability of the vitrimers. Enhanced adhesive properties compared to pristine phenoxy resins are demonstrated, including the possibility to thermally re-join the assembly after its mechanical failure. Finally, the solvent-free preparation of vitrimers is explored at 5% crosslinking density via melt reactive blending, providing a valuable alternative to the less environmentally sustainable synthesis in solution.
Polyethylene Based Ionomers as High Voltage Insulation Materials
Silvia D'Auria, Amir Masoud Pourrahimi, Alessia Favero, Peter Neuteboom, Xiangdong Xu, Shuichi Haraguchi, Marko Bek, Roland Kádár, Enrico Dalcanale, Roberta Pinalli, Christian Müller, Jérôme Vachon
Published online: 30 May 2023
Polyethylene based ionomers are found to be a promising high-voltage insulation material. The synthesized ionomers behave as cross-linked materials with a rubber plateau above the melting temperature and a low direct-current electrical conductivity of 2 to 6·10−14 S m−1 at 70 °C and an electric field of 30 kV mm−1, which is comparable to cross-linked polyethylene, the most widely used insulation material for extruded high-voltage direct-current (HVDC) cables.
New organic platform to integrated photonic device
fabrication
Gustavo Torchia, Cristina Hoppe, César Laia, Jorge Parola and Ginés Lifante-Pedrola
Published online: 15 May 2023
This paper presents a new technological platform for the development of integrated optical circuits for applications in photonics. It is based on supramolecular polymeric materials whose behaviour resembles that of those known as vitrimers. These were synthesized by reaction between diglycidyl ether of bisphenol A (DGEBA) and different n-alkylamines. The photonic characteristics of thin films made from these polymeric systems using the spin coating technique on commercial glass substrates are presented. The reflectivity curves of coupled laser light in the films through a high refractive index prism are also shown and analysed. From these results, thin films show guided modes
in both polarizations (TE-TM) for electromagnetic radiation in the UV-visible range. Likewise, from the experimental data, the refractive index and thickness of the explored films are determined.
2D material hybrid heterostructures: achievements and challenges towards high throughput fabrication
Laura Maggini and Rúben R. Ferreira
Published online: 11 October 2021
2D materials have attracted tremendous attention since the discovery of graphene, because of their unique optical/electronic/mechanical properties, and their manipulable bidimensional morphology. Since forthcoming technologies require a stringent yet faceted portfolio of features, hardly feasible using a single pristine material, the demand for property tuning and multifunctionality has led to the development of hybrid 2D material heterostructures to modulate and exploit the synergy between two or more materials and achieve novel properties. Because of their straightforwardness in implementation and rich variety of possible combinations, these hybrid architectures, held together mostly by non-covalent interactions, virtually allow the fabrication of any kind of assembly offering a unique opportunity for fine-tuning the properties of materials. However, reproducibility, scale-up, assembly into ordered structures and processability are the challenges yet to be addressed to technologically harness their full potential, and enable their integration into mass produced commercial devices. In this perspective article we analyse the recent developments in the automatised production of hybrid solution processed 2D material heterostructures, especially emphasising on the technologies that are currently closer to achieving low-cost, high-throughput standardised production, namely spray coating, inkjet printing and 3D printing, to sense the direction this research field is taking in pursuit of the development of commercialisable products.
