Journal ArticleDOI
Importance of Broad Temperature Windows and Multiple Rheological Approaches for Probing Viscoelasticity and Entropic Elasticity in Vitrimers
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In this article, the authors synthesize polydimethylsiloxane telechelic vitrimers with dynamic boronic ester bonds to investigate the viscoelastic properties of dynamic networks with extremely low Tg via multiple rheological approaches.Abstract:
Model polydimethylsiloxane telechelic vitrimers with dynamic boronic ester bonds were synthesized to investigate the viscoelastic properties of dynamic networks with extremely low Tg via multiple rheological approaches. Frequency sweeps and stress relaxation tests, conducted at more than 120 °C above Tg, show the anticipated Arrhenius behavior of relaxation time with inverse temperature and give the same activation energy for a fixed molecular weight, obtained using a variety of analysis methods. Time–temperature superposition demonstrates that the flow regime is thermorheologically simple, while the modulus of the plateau regime increases with increasing temperature, consistent with a conserved network topology and associative bond exchange. As relaxation times decrease, the rubbery plateau modulus increases, indicating a decoupling of terminal dynamics from mechanics. Below 40 °C, a second Arrhenius regime with lower activation energy emerges, which is attributed to a transition from relaxation dominated by reaction exchange kinetics to relaxation dictated by local polymer dynamics. Our work points to the importance of assessing a broad temperature window and using multiple approaches in probing vitrimers and dynamic networks.read more
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Vitrimers: Current research trends and their emerging applications
Jie Zheng,Zhuang Mao Png,Shi Hoe Ng,Guo Xiong Tham,Enyi Ye,Shermin S. Goh,Xian Jun Loh,Zibiao Li,Zibiao Li +8 more
TL;DR: In this article, a review summarizes the latest progress and developing prospects of vitrimeric materials, and special emphasis is given to vitrimer design strategies which paves the way for development of next-generation circular materials.
Journal ArticleDOI
Ultra-thin self-healing vitrimer coatings for durable hydrophobicity.
Jingcheng Ma,Laura E. Porath,Farhadul Haque,Soumyadip Sett,Kazi Fazle Rabbi,SungWoo Nam,Nenad Miljkovic,Christopher M. Evans +7 more
TL;DR: In this article, the authors present a thin, durable and fluorine-free PDMS-based vitrimer coating that implements many desirable aspects like energy efficiency, durability and sustainability.
Journal ArticleDOI
Vitrimers: Using Dynamic Associative Bonds to Control Viscoelasticity, Assembly, and Functionality in Polymer Networks.
TL;DR: In this article , the role of dynamic covalent chemistry on self-assembly is highlighted in the context of crystallization and nanophase separation, as well as the ability of dynamic bond exchange to manipulate molecular transport and viscoelasticity.
Journal ArticleDOI
A Highly Dynamic Covalent Polymer Network without Creep: Mission Impossible?
TL;DR: In this article , the authors highlight the impact of sharp reactivity changes when applying extrapolation-based approaches during rheological analysis, and they are confident that abandoning the myth of permanent reactivity will aid in the development of sustainable polymeric materials that can truly combine the benefits of thermoplastic and thermoset behavior.
References
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Journal ArticleDOI
Silica-Like Malleable Materials from Permanent Organic Networks
TL;DR: In this paper, the authors designed epoxy networks that can rearrange their topology by exchange reactions without depolymerization, and showed that they are insoluble and processable.
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Vitrimers: permanent organic networks with glass-like fluidity
TL;DR: This mini-review highlights the existing vitrimer systems in the period 2011–2015 with the main focus on their chemical origin.
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Metal-catalyzed transesterification for healing and assembling of thermosets.
TL;DR: Studies of model molecules confirmed that the healing kinetics is controlled by the transesterification reaction rate, and the possibility of varying the catalyst concentration brings control and flexibility of welding and assembling of epoxy thermosets that do not exist for thermoplastics.
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High-performance vitrimers from commodity thermoplastics through dioxaborolane metathesis
Max Rottger,Trystan Domenech,Rob van der Weegen,Antoine J. A. Breuillac,Renaud Nicolaÿ,Ludwik Leibler +5 more
TL;DR: The metathesis of dioxaborolanes is reported, which is rapid and thermally robust, and used to prepare vitrimers from polymers as different as poly(methyl methacrylate), polystyrene, and high-density polyethylene that, although permanently cross-linked, can be processed multiple times by means of extrusion or injection molding.
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Catalytic Control of the Vitrimer Glass Transition
TL;DR: In this paper, the authors show that the transition from liquid to solid is reversible and is, in fact, a glass transition, and they show how to tune the transesterification reaction rate and the broadness of the transition can be controlled at will in epoxy-based vitrimers.