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Shin S, Kwon Y, Hwang C, Jeon W, Yu Y, Paik HJ, Lee W, Kwon MS, Ahn D. Visible-Light-Driven Rapid 3D Printing of Photoresponsive Resins for Optically Clear Multifunctional 3D Objects. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311917. [PMID: 38288894 DOI: 10.1002/adma.202311917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/18/2024] [Indexed: 02/09/2024]
Abstract
Light-driven 3D printing is gaining significant attention for its unparalleled build speed and high-resolution in additive manufacturing. However, extending vat photopolymerization to multifunctional, photoresponsive materials poses challenges, such as light attenuation and interference between the photocatalysts (PCs) and photoactive moieties. This study introduces novel visible-light-driven acrylic resins that enable rapid, high-resolution photoactive 3D printing. The synergistic combination of a cyanine-based PC, borate, and iodonium coinitiators (HNu 254) achieves an excellent printing rate and feature resolution under low-intensity, red light exposure. The incorporation of novel hexaarylbiimidazole (HABI) crosslinkers allows for spatially-resolved photoactivation upon exposure to violet/blue light. Furthermore, a photobleaching mechanism inhibited by HNu 254 during the photopolymerization process results in the production of optically-clear 3D printed objects. Real-time Fourier transform infrared spectroscopy validates the rapid photopolymerization of the HABI-containing acrylic resin, whereas mechanistic evaluations reveal the underlying dynamics that are responsible for the rapid photopolymerization rate, wavelength-orthogonal photoactivation, and observed photobleaching phenomenon. Ultimately, this visible-light-based printing method demonstrates: (i) rapid printing rate of 22.5 mm h-1, (ii) excellent feature resolution (≈20 µm), and (iii) production of optically clear object with self-healing capability and spatially controlled cleavage. This study serves as a roadmap for developing next-generation "smart" 3D printing technologies.
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Affiliation(s)
- Sangbin Shin
- Center for Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
- Department of Polymer Science and Engineering, Pusan National University, Busan, 46241, Republic of Korea
| | - Yonghwan Kwon
- Department of Materials Science and Engineering, Seoul National University (SNU), Seoul, 08826, Republic of Korea
| | - Chiwon Hwang
- Center for Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
- Department of Polymer Science and Engineering, Pusan National University, Busan, 46241, Republic of Korea
| | - Woojin Jeon
- Department of Materials Science and Engineering, Seoul National University (SNU), Seoul, 08826, Republic of Korea
| | - Youngchang Yu
- Center for Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
| | - Hyun-Jong Paik
- Department of Polymer Science and Engineering, Pusan National University, Busan, 46241, Republic of Korea
| | - Wonjoo Lee
- Center for Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
| | - Min Sang Kwon
- Department of Materials Science and Engineering, Seoul National University (SNU), Seoul, 08826, Republic of Korea
| | - Dowon Ahn
- Center for Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
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2
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Jia Y, Qian J, Hao S, Zhang S, Wei F, Zheng H, Li Y, Song J, Zhao Z. New Prospects Arising from Dynamically Crosslinked Polymers: Reprogramming Their Properties. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313164. [PMID: 38577834 DOI: 10.1002/adma.202313164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/18/2024] [Indexed: 04/06/2024]
Abstract
Dynamically crosslinked polymers (DCPs) have gained significant attention owing to their applications in fabricating (re)processable, recyclable, and self-healable thermosets, which hold great promise in addressing ecological issues, such as plastic pollution and resource scarcity. However, the current research predominantly focuses on redefining and/or manipulating their geometries while replicating their bulk properties. Given the inherent design flexibility of dynamic covalent networks, DCPs also exhibit a remarkable potential for various novel applications through postsynthesis reprogramming their properties. In this review, the recent advancements in strategies that enable DCPs to transform their bulk properties after synthesis are presented. The underlying mechanisms and associated material properties are overviewed mainly through three distinct strategies, namely latent catalysts, material-growth, and topology isomerizable networks. Furthermore, the mutual relationship and impact of these strategies when integrated within one material system are also discussed. Finally, the application prospects and relevant issues necessitating further investigation, along with the potential solutions are analyzed.
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Affiliation(s)
- Yunchao Jia
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Jingjing Qian
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Senyuan Hao
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Shijie Zhang
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Fengchun Wei
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Hongjuan Zheng
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Yilong Li
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
| | - Jingwen Song
- School of Materials Science and Engineering, Zhengzhou University, 100 Science Ave., Zhengzhou, 450001, P. R. China
| | - Zhiwei Zhao
- School of Materials Science and Engineering, Henan University of Technology, 100 Lianhua St., Zhengzhou, 450001, P. R. China
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3
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Liu Y, Wang S, Dong J, Huo P, Zhang D, Han S, Yang J, Jiang Z. External Stimuli-Induced Welding of Dynamic Cross-Linked Polymer Networks. Polymers (Basel) 2024; 16:621. [PMID: 38475305 DOI: 10.3390/polym16050621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
Thermosets have been crucial in modern engineering for decades, finding applications in various industries. Welding cross-linked components are essential in the processing of thermosets for repairing damaged areas or fabricating complex structures. However, the inherent insolubility and infusibility of thermoset materials, attributed to their three-dimensional network structure, pose challenges to welding development. Incorporating dynamic chemical bonds into highly cross-linked networks bridges the gap between thermosets and thermoplastics presenting a promising avenue for innovative welding techniques. External stimuli, including thermal, light, solvent, pH, electric, and magnetic fields, induce dynamic bonds' breakage and reformation, rendering the cross-linked network malleable. This plasticity facilitates the seamless linkage of two parts to an integral whole, attracting significant attention for potential applications in soft actuators, smart devices, solid batteries, and more. This review provides a comprehensive overview of dynamic bonds employed in welding dynamic cross-linked networks (DCNs). It extensively discusses the classification and fabrication of common epoxy DCNs and acrylate DCNs. Notably, recent advancements in welding processes based on DCNs under external stimuli are detailed, focusing on the welding dynamics among covalent adaptable networks (CANs).
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Affiliation(s)
- Yun Liu
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150040, China
| | - Sheng Wang
- Key Laboratory of Bio-Based Materials Science & Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Jidong Dong
- Key Laboratory of Bio-Based Materials Science & Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Pengfei Huo
- Key Laboratory of Bio-Based Materials Science & Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Dawei Zhang
- Key Laboratory of Bio-Based Materials Science & Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Shuaiyuan Han
- Key Laboratory of Bio-Based Materials Science & Technology of Ministry of Education, Northeast Forestry University, Harbin 150040, China
| | - Jie Yang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Science, Nanjing Forestry University, Nanjing 210037, China
| | - Zaixing Jiang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150040, China
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4
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Alabiso W, Sölle B, Reisinger D, Guedes de la Cruz G, Schmallegger M, Griesser T, Rossegger E, Schlögl S. On-Demand Activation of Transesterification by Chemical Amplification in Dynamic Thiol-Ene Photopolymers. Angew Chem Int Ed Engl 2023; 62:e202311341. [PMID: 37677110 DOI: 10.1002/anie.202311341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023]
Abstract
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. At the same time, the released acid serves as a catalyst for thermo-activated transesterifications between the deprotected hydroxy and ester moieties. Introduced in an orthogonally cured (450 nm) thiol-click photopolymer, this approach allows for a spatio-temporally controlled activation of bond exchange reactions, which is crucial in light of the creep resistance versus reflow ability trade-off of dynamic polymer networks.
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Affiliation(s)
- Walter Alabiso
- Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700, Leoben, Austria
| | - Bernhard Sölle
- Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700, Leoben, Austria
| | - David Reisinger
- Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700, Leoben, Austria
| | - Gema Guedes de la Cruz
- Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Glöckel-Straße 2, A-8700, Leoben, Austria
| | - Max Schmallegger
- Institute of Physical and Theoretical Chemistry, Stremayrgasse 9/I (A), A-8010, Graz, Austria
| | - Thomas Griesser
- Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Glöckel-Straße 2, A-8700, Leoben, Austria
| | - Elisabeth Rossegger
- Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700, Leoben, Austria
| | - Sandra Schlögl
- Polymer Competence Center Leoben GmbH, Sauraugasse 1, A-8700, Leoben, Austria
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5
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Reisinger D, Kriehuber MU, Bender M, Bautista-Anguís D, Rieger B, Schlögl S. Thermally Latent Bases in Dynamic Covalent Polymer Networks and their Emerging Applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300830. [PMID: 36916976 DOI: 10.1002/adma.202300830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 03/05/2023] [Indexed: 06/16/2023]
Abstract
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. The presented thermally latent base catalyst is conveniently introducible in readily available building blocks and, as proof of concept, applied in a radically polymerized thiol-ene network. Light-mediated curing is used for 3D-printing functional objects, on which the possibility of spatially controlled reshaping and welding based on dynamic transesterification is illustrated. Since the catalyst is thermally activated, limitations regarding sample geometry and optical transparency do not apply, which facilitates a transfer to well-established industrial technologies. Consequently, fiber-reinforced and highly filled magneto-active thiol-ene polymer composites are fabricated by a thermal curing approach. The on-demand activation of dynamic transesterification is demonstrated by (magneto-assisted) reshaping experiments, highlighting a wide range of potential future applications offered by the presented concept.
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Affiliation(s)
- David Reisinger
- Polymer Competence Center Leoben GmbH, Roseggerstraße 12, Leoben, 8700, Austria
| | | | - Marcel Bender
- Processing of Composites Group, Montanuniversität Leoben, Otto Glöckel-Straße 2, Leoben, 8700, Austria
| | | | - Bernhard Rieger
- WACKER-Chair of Macromolecular Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748, Garching, Germany
| | - Sandra Schlögl
- Polymer Competence Center Leoben GmbH, Roseggerstraße 12, Leoben, 8700, Austria
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6
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Dertnig C, Guedes de la Cruz G, Neshchadin D, Schlögl S, Griesser T. Blocked Phosphates as Photolatent Catalysts for Dynamic Photopolymer Networks. Angew Chem Int Ed Engl 2023; 62:e202215525. [PMID: 36421065 DOI: 10.1002/anie.202215525] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/25/2022]
Abstract
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. Introduced in a visible light curable thiol-click photopolymer, the sequence-dependent λ-orthogonality of the curing and cleavage enables an efficient network formation at 451 nm, without premature release of the catalyst. Once cured, irradiation at 372 nm spatiotemporally activates the phosphate, which catalyzes transesterifications at elevated temperature. The formed catalyst has no effect on the thermal stability of the polymeric network and allows the activation of bond exchange reactions in selected domains of printed 3D objects.
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Affiliation(s)
- Carina Dertnig
- Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Glöckel-Straße 2, 8700, Leoben, Austria
| | - Gema Guedes de la Cruz
- Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Glöckel-Straße 2, 8700, Leoben, Austria
| | - Dmytro Neshchadin
- Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, 8010, Graz, Austria
| | - Sandra Schlögl
- Polymer Competence Center Leoben GmbH, Roseggerstraße 12, 8700, Leoben, Austria
| | - Thomas Griesser
- Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Glöckel-Straße 2, 8700, Leoben, Austria
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7
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Shaukat U, Sölle B, Rossegger E, Rana S, Schlögl S. Vat Photopolymerization 3D-Printing of Dynamic Thiol-Acrylate Photopolymers Using Bio-Derived Building Blocks. Polymers (Basel) 2022; 14:polym14245377. [PMID: 36559744 PMCID: PMC9784638 DOI: 10.3390/polym14245377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
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. As a sustainable building block, we synthesized an acrylated linseed oil and mixed it with selected thiol crosslinkers. By careful selection of the transesterification catalyst, we obtained dynamic thiol-acrylate resins with a high cure rate and decent storage stability, which enabled the digital light processing (DLP) 3D-printing of objects with a structure size of 550 µm. Owing to their dynamic covalent bonds, the thiol-acrylate networks were able to relax 63% of their initial stress within 22 min at 180 °C and showed enhanced toughness after thermal annealing. We exploited the thermo-activated reflow of the dynamic networks to heal and re-shape the 3D-printed objects. The dynamic thiol-acrylate photopolymers also demonstrated promising healing, shape memory, and re-shaping properties, thus offering great potential for various industrial fields such as soft robotics and electronics.
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Affiliation(s)
- Usman Shaukat
- Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria
| | - Bernhard Sölle
- Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria
| | - Elisabeth Rossegger
- Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria
| | - Sravendra Rana
- School of Engineering, Energy Acres, University of Petroleum & Energy Studies (UPES), Dehradun 248007, India
- Correspondence: (S.R.); (S.S.); Tel.: +91-9720524191 (S.R.); Tel.: +43-3842-402-2354 (S.S.)
| | - Sandra Schlögl
- Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria
- Correspondence: (S.R.); (S.S.); Tel.: +91-9720524191 (S.R.); Tel.: +43-3842-402-2354 (S.S.)
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8
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Krishna Kumar B, Dickens TJ. Dynamic bond exchangeable thermoset vitrimers in 3D‐printing. J Appl Polym Sci 2022. [DOI: 10.1002/app.53304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Balaji Krishna Kumar
- Department of Industrial & Manufacturing Engineering High‐Performance Materials Institute, FAMU‐FSU College of Engineering Tallahassee Florida USA
| | - Tarik J. Dickens
- Department of Industrial & Manufacturing Engineering High‐Performance Materials Institute, FAMU‐FSU College of Engineering Tallahassee Florida USA
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9
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Shaukat U, Rossegger E, Schlögl S. A Review of Multi-Material 3D Printing of Functional Materials via Vat Photopolymerization. Polymers (Basel) 2022; 14:polym14122449. [PMID: 35746024 PMCID: PMC9227803 DOI: 10.3390/polym14122449] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 02/04/2023] Open
Abstract
Additive manufacturing or 3D printing of materials is a prominent process technology which involves the fabrication of materials layer-by-layer or point-by-point in a subsequent manner. With recent advancements in additive manufacturing, the technology has excited a great potential for extension of simple designs to complex multi-material geometries. Vat photopolymerization is a subdivision of additive manufacturing which possesses many attractive features, including excellent printing resolution, high dimensional accuracy, low-cost manufacturing, and the ability to spatially control the material properties. However, the technology is currently limited by design strategies, material chemistries, and equipment limitations. This review aims to provide readers with a comprehensive comparison of different additive manufacturing technologies along with detailed knowledge on advances in multi-material vat photopolymerization technologies. Furthermore, we describe popular material chemistries both from the past and more recently, along with future prospects to address the material-related limitations of vat photopolymerization. Examples of the impressive multi-material capabilities inspired by nature which are applicable today in multiple areas of life are briefly presented in the applications section. Finally, we describe our point of view on the future prospects of 3D printed multi-material structures as well as on the way forward towards promising further advancements in vat photopolymerization.
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Reisinger D, Dietliker KP, Sangermano M, Schlögl S. Streamlined concept towards spatially resolved photoactivation of dynamic transesterification in vitrimeric polymers by applying thermally stable photolatent bases. Polym Chem 2022. [DOI: 10.1039/d1py01722e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Through a well targeted design, vitrimers are able to reorganise their three-dimensional covalently crosslinked network structure by associative exchange reactions when the so-called topology freezing transition temperature (Tv) is exceeded....
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He E, Yao Y, Zhang Y, Wei Y, Ji Y. Reprocessing of Vitrimer. ACTA CHIMICA SINICA 2022. [DOI: 10.6023/a22020072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Robinson LL, Self JL, Fusi AD, Bates MW, Read de Alaniz J, Hawker CJ, Bates CM, Sample CS. Chemical and Mechanical Tunability of 3D-Printed Dynamic Covalent Networks Based on Boronate Esters. ACS Macro Lett 2021; 10:857-863. [PMID: 35549203 DOI: 10.1021/acsmacrolett.1c00257] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
As the scope of additive manufacturing broadens, interest has developed in 3D-printed objects that are derived from recyclable resins with chemical and mechanical tunability. Dynamic covalent bonds have the potential to not only increase the sustainability of 3D-printed objects, but also serve as reactive sites for postprinting derivatization. In this study, we use boronate esters as a key building block for the development of catalyst-free, 3D-printing resins with the ability to undergo room-temperature exchange at the cross-linking sites. The orthogonality of boronate esters is exploited in fast-curing, oxygen-tolerant thiol-ene resins in which the dynamic character of 3D-printed objects can be modulated by the addition of a static, covalent cross-linker with no room-temperature bond exchange. This allows the mechanical properties of printed parts to be varied between those of a traditional thermoset and a vitrimer. Objects printed with a hybrid dynamic/static resin exhibit a balance of structural stability (residual stress = 18%) and rapid exchange (characteristic relaxation time = 7 s), allowing for interfacial welding and postprinting functionalization. Modulation of the cross-linking density postprinting is enabled by selective hydrolysis of the boronate esters to generate networks with swelling capacities tunable from 1.3 to 3.3.
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