Article
Polymer Science
Loic Buchon, Jean-Michel Becht, Laurent Rubatat, Wei Wang, Hua Wei, Pu Xiao, Jacques Lalevee
Summary: This research synthesized and characterized four potential phosphine oxide photoinitiators and evaluated their efficiency in photopolymerization at 405 nm wavelength. Two of the obtained photoinitiators showed better performance than the widely used commercial photoinitiator. Additionally, one of the synthesized photoinitiators was successfully used in 3D printing of thermoplastics and exhibited lower cytotoxicity compared to the benchmark structure.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Taylor O. Hope, Tamara Reyes-Robles, Keun Ah Ryu, Steven Mauries, Nicole Removski, Jacinthe Maisonneuve, Rob C. Oslund, Olugbeminiyi O. Fadeyi, Mathieu Frenette
Summary: We investigated the photocatalytic activation of phenols for tyrosine labelling using flavin-based photocatalysts, and found that the initial covalent binding between phenols and tyrosine is not radical addition, but radical-radical recombination. This proposed mechanism may also explain the mechanism of other reported tyrosine-tagging approaches. Competitive kinetics experiments showed the generation of phenoxyl radicals through multiple pathways involving the excited riboflavin-photocatalyst or singlet oxygen, increasing the likelihood of radical-radical recombination.
Article
Chemistry, Multidisciplinary
Zilong Wu, Wenbo Fang, Chenyu Wu, Nathaniel Corrigan, Tong Zhang, Sihao Xu, Cyrille Boyer
Summary: In this study, we report an aqueous and near-infrared light mediated photoinduced reversible addition-fragmentation chain transfer polymerization system. With the high catalytic efficiency and excellent oxygen tolerance, this system allows fast synthesis of well-controlled polymers, even in the presence of non-transparent barriers. We further demonstrate the synthesis of polymeric nanoparticles with consistent morphologies through thick barriers, utilizing the advantages of NIR wavelengths.
Article
Polymer Science
James B. Young, Jared Bowman, Cabell B. Eades, Alexander J. Wong, Brent S. Sumerlin
Summary: Controlled radical polymerization techniques allow for the synthesis of polymers with specific molecular weights and architectures. In this study, the role of light in triggering thermal depolymerization of polymers synthesized through reversible-addition-fragmentation chain-transfer (RAFT) polymerization was investigated. By targeting specific electronic transitions, the depolymerization efficiency was enhanced.
Article
Polymer Science
Soren Schumacher, Sanwardhini Pantawane, Stephan Gekle, Seema Agarwal
Summary: The synthesis and polymerization behavior of four different monofunctional vinyl cyclopropane (VCP) derivatives were investigated. The study found that different VCPs have varying abilities to form hydrogen bonds in their side chains, leading to preorganization and potentially faster polymerization. Although VCPs capable of hydrogen bonding did not show significant differences, a general effect of hydrogen bonds on polymerization behavior was observed.
Article
Chemistry, Physical
Ilona Pyszka, Zdzislaw Kucybala, Beata Jedrzejewska
Summary: A series of dyes based on the phenazine skeleton were synthesized and investigated as potential singlet oxygen sensitizers and visible light absorbers in dye photoinitiating systems for radical polymerization. The effectiveness of the dye photoinitiating system depended on the arrangement of aromatic rings and the number of nitrogen atoms in the modified phenazine structure, as well as the quantum yield of the triplet state formation in the visible light region.
Article
Engineering, Environmental
Lingwei Gao, Yang Guo, Juhong Zhan, Gang Yu, Yujue Wang
Summary: This study evaluated the effects of various quenchers on the mechanism of a cobalt mediated peroxymonosulfate (Co(II)/PMS) process and found that these quenchers not only quench target reactive species but also cause interference effects. Therefore, caution should be exercised when applying the quenching method to investigate the mechanism of the persulfate-based process.
Article
Polymer Science
Paulina Bednarczyk, Izabela Irska, Konrad Gziut, Paula Ossowicz-Rupniewska
Summary: A series of novel multifunctional epoxy (meth)acrylate resins have been synthesized in this work, which have both epoxides and carbon-carbon double bonds and can be crosslinked through different mechanisms. The structure and properties of the synthesized resins were studied to formulate photocurable coating compositions.
Article
Polymer Science
Jiyuan Sun, Shusu Ren, Haitao Zhao, Shunhu Zhang, Xiang Xu, Lifen Zhang, Zhenping Cheng
Summary: To overcome the challenges of long wavelength-photocontrolled radical polymerization in aqueous solutions and the limitations of conventional near-infrared (NIR) photocatalysts, a series of beta-tetra-substituted water-soluble zinc phthalocyanines (beta-TS-Zns) were designed and synthesized as NIR photocatalysts for reversible addition-fragmentation chain transfer (RAFT) polymerization. The NIR photocatalysts can also be polymerizable monomers and covalently loaded on the polymer chains, enabling permanent NIR photocatalysis. The polymerization can be conducted in water and phosphate buffer saline (PBS) solution, producing polymers with controlled molar mass and narrow dispersities.
Article
Polymer Science
Jiyuan Sun, Shusu Ren, Haitao Zhao, Shunhu Zhang, Xiang Xu, Lifen Zhang, Zhenping Cheng
Summary: To overcome the challenges of long wavelength-photocontrolled radical polymerization in aqueous solutions and the limitations of post-treatment of conventional near-infrared (NIR) photocatalysts (PCs), we developed and synthesized a series of beta-tetra-substituted water-soluble zinc phthalocyanines (beta-TS-Zns) as NIR PCs. These NIR PCs exhibited efficient reversible addition-fragmentation chain transfer (RAFT) polymerization under NIR light irradiation, and could also be covalently loaded on polymer chains for permanent NIR photocatalysis. The polymerization could be conducted in water and phosphate buffer saline (PBS) solution, producing polymers with controlled molar mass and narrow dispersities (D = 1.03-1.25). This NIR-photocontrolled aqueous RAFT polymerization system holds promise for applications in tissue engineering biomaterials benefiting from the high penetration ability of NIR light.
Article
Engineering, Chemical
Chen Yang, Zhongzhu Yang, Kaihua Yang, Zhigang Yu, Yize Zuo, Longjie Cheng, Yibo Wang, Hui Sun, Guanlong Yu, Chang Zhang, Xin Li
Summary: Four different crystalline phases of MnO2 catalysts were prepared for the effective activation of periodate in tetracycline hydrochloride degradation. Delta-MnO2 exhibited superior catalytic activity, attributed to the crucial role of oxygen vacancy in periodate activation on the MnO2 surface.
SEPARATION AND PURIFICATION TECHNOLOGY
(2022)
Review
Polymer Science
Philipp Marx, Frank Wiesbrock
Summary: The review highlights the use of expanding monomers as a strategy to overcome volumetric shrinkage during polymerization. These monomers exhibit cyclic or oligocyclic structures that result in volumetric expansion or reduced shrinkage during the ring-opening reaction. The most prominent classes of expanding monomers discussed include cycloalkanes and cycloalkenes, oxacycles, benzoxazines, as well as thiocyclic compounds.
Article
Polymer Science
I Zaborniak, P. Chmielarz
Summary: Radical polymerization techniques utilizing naturally occurring substances, such as riboflavin, are being rapidly developed towards more sustainable and environmentally friendly approaches. Riboflavin's unique structure and biological activity make it an excellent target for radical polymerization, with its versatile properties that allow for easy modification to incorporate additional functional groups. Recent advances in utilizing riboflavin structure to mediate free radical polymerization and controlled polymerization techniques offer environmentally friendly and easily scalable methods for the preparation of functional polymer materials with diverse applications.
EUROPEAN POLYMER JOURNAL
(2021)
Article
Chemistry, Physical
Xinquan Zhou, Ali Jawad, Mengyi Luo, Chunguang Luo, Tingting Zhang, Huabin Wang, Jia Wang, Songlin Wang, Zhulei Chen, Zhuqi Chen
Summary: The study found that incorporating unreducible metal oxides into CuO hybrid magnetic nano ferric oxide can alter the reaction pathway and increase the reaction rate in persulfate activation. In the CuM@Fe3O4/PMS system, O-1(2) dominates the nonradical oxidation process, indicating the importance of singlet oxygen in the system.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Chemistry, Multidisciplinary
Tadashi Kanbara, Mizuki Arase, Miyu Tanaka, Airi Yamaguchi, Koto Tagami, Tomoko Yajima
Summary: In this study, synthesis methods for fluorine-containing polymers were developed using photoirradiation halogen bonding. Sequential polymerization resulted in fluoroalkyl-alkyl-alternating polymers, while chain polymerization produced polymers with perfluoroalkyl terminals. Block polymers were also synthesized through successive chain polymerization.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Physical
Markus Lunzer, Joseph S. Beckwith, Franziska Chalupa-Gantner, Arnulf Rosspeintner, Giuseppe Licari, Wolfgang Steiger, Christian Hametner, Robert Liska, Johannes Froehlich, Eric Vauthey, Aleksandr Ovsianikov, Brigitte Holzer
Summary: A series of soluble and symmetric chalcogenophenes have been designed and synthesized as potential two-photon absorption initiators. The photophysical analysis reveals their good 2PA properties, especially the strong influence of selenium on 2PA cross sections, making them promising new 2PA photoinitiators. The efficiency and spectral versatility of two selenium-containing lead compounds have been confirmed through structuring and threshold tests, showing superior reactivity and dose compared to commercial initiators.
CHEMISTRY OF MATERIALS
(2022)
Article
Polymer Science
Yazgan Mete, Konstanze Seidler, Christian Gorsche, Thomas Koch, Patrick Knaack, Robert Liska
Summary: This study presents a novel approach to 3D print polyesters directly from ε-caprolactone via stereolithography at elevated temperatures. The introduction of low amounts of crosslinkers improves the stability of the structure while maintaining its degradability and semicrystallinity. The study also highlights the significant influence of the amount and type of crosslinker on the material properties.
POLYMER INTERNATIONAL
(2022)
Article
Polymer Science
Lorenzo Pezzana, Raffael Wolff, Giuseppe Melilli, Nathanael Guigo, Nicolas Sbirrazzuoli, Jurgen Stampfl, Robert Liska, Marco Sangermano
Summary: The introduction of Hot Lithography has opened up new possibilities for high viscous formulations in additive manufacturing. By increasing the temperature during the 3D printing process, the viscosity of the resin is reduced and higher curing kinetics and degree of conversion can be achieved. This allows for the printing of a wider range of epoxy-based formulations, including those that are not reactive enough at room temperature. Two bio-based epoxy monomers were investigated for their use in Hot Lithography 3D printing, and their performance was compared to a commercial fossil-based resin. The photocuring process and the thermo-mechanical properties of the final thermosets were thoroughly studied, and the potential for printing complex shapes was demonstrated.
Article
Chemistry, Physical
Carola Haslinger, Lukas P. Leutgeb, Michael Haas, Stefan Baudis, Robert Liska
Summary: This study synthesized two novel tetraacylgermanes and evaluated their potential for ceramic manufacturing. The results showed that these compounds exhibited comparable absorption and photoreactivity to the commercial benchmark substance.
Article
Materials Science, Multidisciplinary
Roland Taschner, Robert Liska, Patrick Knaack
Summary: Iodonium antimonates and borates are widely used initiators in polymerization, while cyanide-ligated borane B2 is a new type of initiator with high reactivity and cost-effectiveness.
ACS APPLIED POLYMER MATERIALS
(2022)
Article
Polymer Science
Barbara Dellago, Altan Alpay Altun, Robert Liska, Stefan Baudis
Summary: Vinyl esters (VEs) have been extensively studied as monomers for additive manufacturing in tissue engineering due to their low cytotoxicity, good biocompatibility, and favorable degradation behavior. However, crosslinked VEs have poor mechanical properties, especially brittleness. A previous study found that covalently incorporating high molecular weight additives into the vinyl ester-thiol network can overcome this issue. In this work, poly(epsilon-caprolactone)-based additives modified with photopolymerizable end groups were used to improve the mechanical properties, specifically toughness, and to enable application in digital light processing stereolithography. Different toughness-enhancing additives and their effects on photochemical and (thermo)mechanical characteristics were investigated, as well as the impact of commercial flexible and synthesized rigid thiols on these properties. The results showed that the covalently incorporated toughness enhancers significantly improved the mechanical properties, particularly tensile toughness, without sacrificing photoreactivity.
JOURNAL OF POLYMER SCIENCE
(2023)
Article
Polymer Science
Benjamin Grob, Benedikt Frieser, Robert Liska, Yohann Catel
Summary: Polymerization shrinkage and shrinkage stress are crucial issues in dental restorations. Addition fragmentation chain transfer agents (AFCT agents) are effective in reducing shrinkage stress. Four novel polymerizable allyl sulfides were synthesized and evaluated in dental composites. AFCT-based composites showed good performance.
EUROPEAN POLYMER JOURNAL
(2022)
Correction
Polymer Science
Benjamin Grob, Benedikt Frieser, Robert Liska, Yohann Catel
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Katharina Gallas, Dominik Wohlmuth, Zhiquan Li, Aliasghar Ajami, Aleksandr Ovsianikov, Robert Liska, Christian Slugovc
Summary: This study reports the synthesis of two dye-labeled azides through de-symmetrization using a copper (I)-catalyzed alkyne-azide cycloaddition (CuAAC) method. Dansyl derivative and perylene diimide derivative with alkyne functional groups were employed as the fluorescent dyes. The photo-physical properties of these dye dyads were described, and their performance in multi-photon grafting onto polyethylene glycol-based hydrogels was investigated. It was found that the dansyl-conjugated BAC derivative was suitable for multi-photon grafting with lasers operating at 800 nm, while the perylene diimide-bearing dye did not yield the desired result.
MONATSHEFTE FUR CHEMIE
(2023)
Article
Chemistry, Applied
Stephan Schandl, Thomas Koch, Juergen Stampfl, Katharina Ehrmann, Robert Liska
Summary: Aliphatic polycarbonates are highly regarded for being sustainable, biodegradable, and biocompatible. Recently, photobase generators have made cyclic carbonates available for light-induced anionic ring-opening polymerization, leading to the formation of pure aliphatic polycarbonate networks. The polymerization mechanism was investigated using photo-DSC and photorheology on synthesized cyclic carbonates. Different ratios of reactive diluent to crosslinker were tested to obtain materials with tunable mechanical properties.
REACTIVE & FUNCTIONAL POLYMERS
(2023)
Article
Chemistry, Applied
Lisa Staubmann, Agnes Mistlberger-Reiner, El Mehdi Raoui, Gertrude Brunner, Lisa Sinawehl, Marion Winter, Robert Liska, Marc Pignitter
Summary: This study investigates the stabilizing effects of pectin, guar gum, locust bean gum, and their combinations on ready-to-drink beverages containing 7% orange juice. Results show that in beverages with larger juice particles (0.6-200 μm), using 2.5 g pectin and 2.5 g guar gum per kg base is most suitable for stabilizing turbidity, while in beverages with smaller juice particles (0.5-120 μm), using 2 g pectin or 2.5 g pectin and 2.5 g locust bean gum per kg base can maintain stability. The combination of hydrocolloids has greater effects on long-term storage stability of the beverages compared to individual stabilizers.
FOOD HYDROCOLLOIDS
(2023)
Article
Engineering, Manufacturing
Viola Hobiger, Anna-Lea Kutsch, Juergen Stampfl, Robert Liska, Stefan Baudis, Peter Krajnc
Summary: A highly reactive thiol-ene high internal phase emulsion was developed for light-driven additive manufacturing, resulting in highly porous customizable poly(high internal phase emulsion) materials. The formulation facilitates short irradiation times and low amounts of photoinitiator, while avoiding the need for harmful solvents. The addition of a selected thiol as a chain-transfer agent improves the brittleness of the acrylate-based system and potential oxygen inhibition, producing printed layers with a thickness<50 μm and an average pore size<5 μm.
3D PRINTING AND ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Roland Taschner, Thomas Koch, Raffael Wolff, Juergen Stampfl, Robert Liska, Patrick Knaack
Summary: Sulfonium hexafluorophosphates and perfluorinated tetraphenylborates are established initiators in cationic photopolymerization. The cyanide-ligated borane-based photoinitiator B2 outperforms commercial initiators in terms of molecular weight, cost, and reactivity. In addition, B2 shows excellent thermal and storage stability, and can be sensitized by anthracene derivatives. When used in hot lithography at 90°C, B2 exhibits superior layer quality and coloration compared to existing sulfonium initiators.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Polymer Science
Larissa Alena Ruppitsch, Jakob Ecker, Thomas Koch, Katharina Ehrmann, Juergen Stampfl, Robert Liska
Summary: Supramolecular polymers play a significant role in influencing dynamic mechanical properties in slightly crosslinked polymer networks. The introduction of 2-ureido-4[1H]-pyrimidinones (UPy) as supramolecular building blocks in photopolymerizable systems brings about dynamic behavior. This study investigates the impact of UPy-motif on reactivity and (thermo)mechanical properties through various testing methods. Furthermore, the UPy-based photopolymerizable system is successfully applied in Hot Lithography printing to create complex 3D-printed parts with high precision.
JOURNAL OF POLYMER SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Roland Taschner, Thomas Koch, Raffael Wolff, Jurgen Stampfl, Robert Liska, Patrick Knaack
Summary: Sulfonium hexafluorophosphates and perfluorinated tetraphenylborates are commonly used initiators in cationic photopolymerization and have been applied in 3D-printing at high temperatures. The cyanide-ligated borane-based photoinitiator B2 shows higher reactivity and lower cost compared to other borates. B2 exhibits excellent performance in epoxy monomer conversions at a wide range of temperatures. In addition, B2-based formulations are stable and can be sensitized by anthracene derivatives. B2 also outperforms existing sulfonium initiators in terms of layer quality and coloration in hot lithography.
ACS APPLIED POLYMER MATERIALS
(2023)
