Recyclable poly(thiourethane) vitrimers with high Tg. Influence of the isocyanate structure

Gamardella, Francesco; Flor, Silvia De la; Ramis, Xavier; Serra, À.

doi:10.1016/j.reactfunctpolym.2020.104574

Cited by 49 publications

(54 citation statements)

References 37 publications

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“…For these materials, a dissociative mechanism was proposed, in absence of free hydroxyl groups in the network, although the relaxation studies showed a vitrimer-like behavior without any sudden decrease in viscosity, fitting an Arrhenius model. Similarly, in our studies, a vitrimeric behavior was observed in the case of poly(thiourethane) networks prepared with a tin-catalyst [6,7].…”

Section: Introductionsupporting

confidence: 84%

“…In both studies, a tin-catalyst was used and the influence of the amount of the catalyst on the relaxation rate was demonstrated. When comparing the relaxation behavior of poly(thiourethane) and poly(urethane) networks, it can be observed that the activation energy, E a , is significantly lower for the former (between 70 and 100 kJ/mol) [6,7] than for the latter (around 140 kJ/mol) [13], which confirms the kinetic effect produced by the substitution of oxygen by sulfur.…”

Section: Introductionmentioning

confidence: 74%

“…Moreover, since thiols are more acidic than alcohols and sulfide anions are more nucleophilic than alkoxides and better leaving groups, some positive kinetic effects in the bond interchange of poly(thiourethane)s could be foreseen. In two previous papers from our research group [6,7], we proved the existence of a reversible thiocarbamate exchange reaction in PTUs and the possibility to recycle them. In both studies, a tin-catalyst was used and the influence of the amount of the catalyst on the relaxation rate was demonstrated.…”

Section: Introductionmentioning

confidence: 84%

“…Recently, networked poly(thiourethane)s (PTUs) have been reported as a new class of CANs thanks to the presence of thiourethane groups that can undergo exchange reactions at moderate temperatures [5][6][7][8]. PTUs are formed by the very efficient coupling reaction between thiols and 2 of 18 isocyanate, which, in the presence of a base catalyst, can be considered a click-type reaction.…”

Section: Introductionmentioning

confidence: 99%

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Recyclable Organocatalyzed Poly(Thiourethane) Covalent Adaptable Networks

et al. 2020

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A new type of tetraphenylborate salts derived from highly basic and nucleophilic amines, namely 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) and triazabicyclodecene (TBD), was applied to the preparation of networked poly(thiourethane)s (PTUs), which showed a vitrimer-like behavior, with higher stress-relaxation rates than PTUs prepared by using dibutyl thin dilaurate (DBTDL) as the catalyst. The use of these salts, which release the amines when heated, instead of the pure amines, allows the formulation to be easily manipulated to prepare any type of samples. The materials prepared from stoichiometric mixtures of hexamethylene diisocyanate (HDI), trithiol (S3) and with a 10% of molar excess of isocyanate or thiol were characterized by FTIR, thermomechanical analysis, thermogravimetry, stress-relaxation tests and tensile tests, thus obtaining a complete thermal and mechanical characterization of the materials. The recycled materials obtained by grinding the original PTUs and hot-pressing the small pieces in the optimized time and temperature conditions were fully characterized by mechanical, thermomechanical and FTIR studies. This allowed us to confirm their recyclability, without appreciable changes in the network structure and performance. From several observations, the dissociative interchange trans-thiocarbamoylation mechanism was evidenced as the main responsible of the topological rearrangements at high temperature, resulting in a vitrimeric-like behavior.

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Section: Introductionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

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Recyclable Organocatalyzed Poly(Thiourethane) Covalent Adaptable Networks

et al. 2020

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“…The relaxation was faster when the amount of catalyst increased [130]. We also reported the possibility of reshaping or recycling crosslinked poly(thiourethane)s with T g s of around 130 • C [131].…”

Section: Poly(thiourethane) Network By Thiol-isocyanate Reactionmentioning

confidence: 68%

The Use of Click-Type Reactions in the Preparation of Thermosets

et al. 2020

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Click chemistry has emerged as an effective polymerization method to obtain thermosets with enhanced properties for advanced applications. In this article, commonly used click reactions have been reviewed, highlighting their advantages in obtaining homogeneous polymer networks. The basic concepts necessary to understand network formation via click reactions, together with their main characteristics, are explained comprehensively. Some of the advanced applications of thermosets obtained by this methodology are also reviewed.

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Sulfur in Dynamic Covalent Chemistry

Orrillo

Furlán

2022

Angewandte Chemie

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Sulfur has been important in dynamic covalent chemistry (DCC) since the beginning of the field. Mainly as part of disulfides and thioesters, dynamic sulfur‐based bonds (DSBs) have a leading role in several remarkable reactions. Part of this success is due to the almost ideal properties of DSBs for the preparation of dynamic covalent systems, including high reactivity and good reversibility under mild aqueous conditions, the possibility of exploiting supramolecular interactions, access to isolable structures, and easy experimental control to turn the reaction on/off. DCC is currently witnessing an increase in the importance of DSBs. The chemical flexibility offered by DSBs opens the door to multiple applications. This Review presents an overview of all the DSBs used in DCC, their applications, and remarks on the interesting properties that they confer on dynamic chemical systems, especially those containing several DSBs.

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Recyclable poly(thiourethane) vitrimers with high Tg. Influence of the isocyanate structure

Cited by 49 publications

References 37 publications

Recyclable Organocatalyzed Poly(Thiourethane) Covalent Adaptable Networks

Recyclable Organocatalyzed Poly(Thiourethane) Covalent Adaptable Networks

The Use of Click-Type Reactions in the Preparation of Thermosets

Sulfur in Dynamic Covalent Chemistry

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