92 results match your criteria: "Polymer Competence Center Leoben GmbH[Affiliation]"
J Am Chem Soc
December 2024
Polymer Competence Center Leoben GmbH, Sauraugasse 1, 8700 Leoben, Austria.
While latent catalysts have become a well-established strategy for locally and temporally controlling bond exchange reactions in dynamic polymer networks, there is a lack of inherently tailorable systems. Herein, we introduce a thiol-ene network based on disulfide exchange that alters its dynamic properties as a function of the color of light used during the curing reaction. For this purpose, selected allyl-bearing disulfides are synthesized, which are transparent at 450 nm but undergo disulfide scission upon 365 nm light irradiation, as confirmed by UV-vis and EPR measurements.
View Article and Find Full Text PDFPolymers (Basel)
October 2024
Polymer Competence Center Leoben GmbH (PCCL), Sauraugasse 1, 8700 Leoben, Austria.
Dynamic polymer networks combine the noteworthy (thermo)mechanical features of thermosets with the processability of thermoplastics. They rely on externally triggered bond exchange reactions, which induce topological rearrangements and, at a sufficiently high rate, a macroscopic reflow of the polymer network. Due to this controlled change in viscosity, dynamic polymers are repairable, malleable, and reprocessable.
View Article and Find Full Text PDFAdv Mater
November 2024
Polymer Competence Center Leoben GmbH, Sauraugasse 1, Leoben, 8700, Austria.
Dynamic covalent polymer networks exhibit a cross-linked structure like conventional thermosets and elastomers, although their topology can be reorganized through externally triggered bond exchange reactions. This characteristic enables a unique combination of repairability, recyclability and dimensional stability, crucial for a sustainable industrial economy. Herein the application of a photoswitchable nitrogen superbase is reported for the spatially resolved and reversible control over dynamic bond exchange within a thiol-ene photopolymer.
View Article and Find Full Text PDFVitrimers are polymer networks with covalent bonds that undergo reversible exchange reactions and rearrange their topology in response to an external stimulus. The temperature-dependent change in viscoelastic properties is conveniently adjusted by selected catalysts. In these thermo-activated systems, the lack in spatial control can be overcome by using photolatent catalysts.
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July 2024
Department of Polymer Engineering and Science, Chair of Polymer Processing, Montanuniversitaet Leoben, Franz-Josef Straße 18, 8700 Leoben, Austria.
Selecting the optimal settings for the production of rubber goods can be a very time-consuming and resource-intensive process. A promising method for optimizing rubber processing in a short period of time is the use of simulation routines. However, process simulations have only recently enabled meaningful predictions of not only the part's state of cure but also its mechanical characteristics.
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May 2024
Politecnico di Torino, Department of Applied Science and Technology, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Additive manufacturing (AM) has revolutionised the manufacturing industry, offering versatile capabilities for creating complex geometries directly from a digital design. Among the various 3D printing methods for polymers, vat photopolymerisation combines photochemistry and 3D printing. Despite the fact that single-epoxy 3D printing has been explored, the fabrication of multi-material bioderived epoxy thermosets remains unexplored.
View Article and Find Full Text PDFMaterials (Basel)
April 2024
Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700 Leoben, Austria.
Driven by environmental considerations, the scientific community has directed great effort towards the synthesis of new materials derived from renewable resources. However, for photocurable resins, most commercially available building blocks still rely on petroleum-based precursors. Herein, we present a simple synthesis route for bio-based acrylate-modified polyester resins, whose viscosity is sufficiently low for processing them with vat photopolymerization 3D printing.
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January 2024
Faculty of Petrochemistry and Polymer Materials, Mendeleev University of Chemical Technology, Miusskaya Sq. 9, 125047 Moscow, Russia.
An analysis of the influence of common modifiers on the kinetics of the curing process of epoxy-anhydride vitrimers was carried out. As common modifiers to enhance the "vitrimeric" nature of the material, zinc acetylacetonate as a transesterification catalyst and glycerol as a modifier of hydroxyl group content were chosen. The curing process of all obtained compositions was studied by differential scanning calorimetry (DSC) followed by the application of the isoconversional approach.
View Article and Find Full Text PDFWaste Manag Res
September 2024
Polymer Competence Center Leoben GmbH, Leoben, Austria.
The use of the polypropylene (PP) recyclates in certain processing methods and applications is still limited by their quality. The high melt flow rate (MFR) and the inconsistent properties of recyclates are common obstacles to their use. Therefore, this work aims to identify possible reasons for the low and inconsistent quality of PP recyclates depending on the source material in PP waste bales.
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September 2023
Institut Charles Sadron, Université de Strasbourg, CNRS, F-67000 Strasbourg, France.
Structured surfaces, which are the basis of the lotus blossom effect, have great potential to serve/operate as functionalised surfaces, i.e., surfaces with specific and/or adjustable properties.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2023
Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700, Leoben, Austria.
Chemical amplification is a well-established concept in photoresist technology, wherein one photochemical event leads to a cascade of follow-up reactions that facilitate a controlled change in the solubility of a polymer. Herein, we transfer this concept to dynamic polymer networks to liberate both catalyst and functional groups required for bond exchange reactions under UV irradiation. For this, we exploit a photochemically generated acid to catalyse a deprotection reaction of an acid-labile tert-butoxycarbonyl group, which is employed to mask the hydroxy groups of a vinyl monomer.
View Article and Find Full Text PDFFront Robot AI
July 2023
Brubotics, Vrije Universiteit Brussel (VUB) and Imec, Brussels, Belgium.
The variability in the shapes and sizes of objects presents a significant challenge for two-finger robotic grippers when it comes to manipulating them. Based on the chemistry of vitrimers (a new class of polymer materials that have dynamic covalent bonds, which allow them to reversibly change their mechanical properties under specific conditions), we present two designs as 3D-printed shape memory polymer-based shape-adaptive fingertips (SMP-SAF). The fingertips have two main properties needed for an effective grasping.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2023
Montanuniversität Leoben, Institute of Chemistry of Polymeric Materials, Otto-Glöckel-Strasse 2, A-8700 Leoben, Austria.
Since surface-initiated photopolymerization techniques have gained increasing interest within the last decades, the coupling of photoinitiators to surfaces and particles has become an important research topic in material and surface sciences. In terms of surface modification and functionalization, covalently coupled photoinitiators and subsequent photopolymerizations are employed to provide a huge variety of surface properties, such as wettability, stimulus responsive features, antifouling behavior, protein binding, friction control, drug delivery, and many more. For this purpose, numerous type I and type II photoinitiators or other photosensitive moieties have been attached to different substrates so far.
View Article and Find Full Text PDFAdditive manufacturing is one of the most promising processing techniques for fabricating customized 3D objects. For the 3D printing of functional and stimuli-triggered devices, interest is steadily growing in processing materials with magnetic properties. Synthesis routes for magneto-responsive soft materials typically involve the dispersion of (nano)particles into a non-magnetic polymer matrix.
View Article and Find Full Text PDFAdv Mater
June 2023
Polymer Competence Center Leoben GmbH, Roseggerstraße 12, Leoben, 8700, Austria.
A novel strategy allowing temporal control of dynamic bond exchange in covalently crosslinked polymer networks via latent transesterification catalysts is introduced. Obtained by a straightforward air- and water-tolerant synthesis, the latent catalyst is designed for an irreversible temperature-mediated release of a strong organic base. Its long-term inactivity at temperatures below 50 °C provides the unique opportunity to equip dynamic covalent networks with creep resistance and high bond-exchange rates, once activated.
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February 2023
Politecnico di Torino, Department of Applied Science and Technology, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Vitrimers brought new properties in thermosets by allowing their reshaping, self-healing, reprocessing, and network rearrangement without changing structural integrity. In this study, epoxidized castor oil (ECO) was successfully used for the straightforward synthesis of a bio-based solvent-free vitrimer. The synthesis was based on a UV-curing process, which proceeded at low temperatures in the absence of any solvents, and within a short time.
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December 2022
Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria.
As an energy-efficient additive manufacturing process, vat photopolymerization 3D-printing has become a convenient technology to fabricate functional devices with high resolution and freedom in design. However, due to their permanently crosslinked network structure, photopolymers are not easily reprocessed or repaired. To improve the environmental footprint of 3D-printed objects, herein, we combine the dynamic nature of hydroxyl ester links, undergoing a catalyzed transesterification at elevated temperature, with an acrylate monomer derived from renewable resources.
View Article and Find Full Text PDFRSC Adv
November 2022
Chemistry of Functional Polymers, Polymer Competence Center Leoben GmbH Roseggerstraße 12 A-8700 Leoben Austria
Angew Chem Int Ed Engl
March 2023
Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Glöckel-Straße 2, 8700, Leoben, Austria.
While latent catalysts are a well-established strategy for initiating and controlling the rate of polymerization reactions, their use in dynamic polymer networks is still in its infancy. The ideal latent catalyst should be thermally stable and release a highly active species in response to an external trigger. Here, we have synthesized a temperature resistant (>200 °C) organic phosphate with a photolabile o-nitrobenzyl protecting group that can be cleaved by UV light.
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October 2022
Department of Polymer Engineering and Science, Polymer Processing, Montanuniversitaet Leoben, Otto Gloeckel-Strasse 2, 8700 Leoben, Austria.
Predicting the curing behaviour of industrially employed elastomeric compounds under typical processing conditions in a reliable and scientifically driven way is important for rubber processing simulation routines, such as injection moulding. Herein, a rubber process analyser was employed to study the crosslinking kinetics of solid silicone rubber based on the concentration of dicumylperoxide. A model was proposed to describe the optimal cure time variation with peroxide concentration and temperature, based on the analysis of processing parameters applying kinetic and thermodynamic judgments.
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September 2022
Chair of Waste Processing Technology and Waste Management, Department of Environmental and Energy Process Engineering, Montanunigersitaet Leoben, Franz Josef Straße 18, 8700 Leoben, Austria.
Small plastic packaging films make up a quarter of all packaging waste generated annually in Austria. As many plastic packaging films are multilayered to give barrier properties and strength, this fraction is considered hardly recyclable and recovered thermally. Besides, they can not be separated from recyclable monolayer films using near-infrared spectroscopy in material recovery facilities.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2023
Polymer Competence Center Leoben GmbH, Roseggerstraße 12, Leoben, 8700, Austria.
Orthogonal photoreactions provide a unique way to locally and independently control (thermo)mechanical properties and functionality of polymer networks simply by choice of the wavelength. Herein, a library of acrylate functional coumarin monomers is synthesized, which are cured by sequence-dependent wavelength orthogonality. In the presence of a long wavelength absorbing photoinitiator, the monomers undergo rapid curing by visible light induced radical chain growth polymerization.
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September 2022
Polymer Competence Center Leoben GmbH, Roseggerstraße 12, 8700 Leoben, Austria.
This work covers a lifecycle assessment of monolayer and multilayer films to quantify the environmental impacts of changing the management of plastic film waste. This lifecycle assessment offers the possibility of quantifying the environmental impacts of processes along the lifecycle of monolayer and multilayer films and mapping deviating impacts due to changed process parameters. Based on the status quo, the changes in global warming potential and abiotic fossil resource depletion were calculated in different scenarios.
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August 2022
Institute of Polymer Processing and Digital Transformation, Johannes Kepler University Linz, Altenberger str. 69, 4040 Linz, Austria.
Automatic in-line process quality control plays a crucial role to enhance production efficiency in the injection molding industry. Industry 4.0 is leading the productivity and efficiency of companies to minimize scrap rates and strive for zero-defect production, especially in the injection molding industry.
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August 2022
Polymer Competence Center Leoben GmbH, Roseggerstraße 12, A-8700 Leoben, Austria.
Models describing how fillers affect the barrier properties of polymers remain an important research topic to improve applications such as hydrogen storage or food preservation. The Nielsen model, one of the earliest models for such predictions, is still one of the most widely used in the literature. However, it does not provide quantitative information on arrangements of fillers inside a polymer matrix, which is crucial for the definition of suitable filler distributions in barrier materials.
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