Phenoxy resin-based vinylogous urethane covalent adaptable networks

Soavi, Giuseppe; Portone, Francesca; Battegazzore, Daniele; Paravidino, Chiara; Arrigo, Rossella; Pedrini, Alessandro; Pinalli, Roberta; Fina, Alberto; Dalcanale, Enrico

doi:10.1016/j.reactfunctpolym.2023.105681

Cited by 2 publications

(2 citation statements)

References 21 publications

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“…1 To investigate the kinetics of the relaxation phenomena, stress relaxation tests were carried out at different temperatures (Figure 2). While the relaxation of vitrimers based on the starshaped polymers are expected to result in multiple relaxation modes, owing to possible dangling chains and non-cross-linked fractions, 31 the relaxation times obtained are very well fitted by the Arrhenius plots, yielding activation energy for the relaxation process in the range of 60 kJ/mol for both S41K-V and S42K-V, while a lower value was obtained for S62K-V. As already observed for the rheological behavior, it is possible to hypothesize that the 6-arm PCL structure allows greater mobility, and the corresponding network is consequently characterized by a lower activation energy compared to systems prepared from 4-arm PCL. Overall, the activation energies for the relaxation of PCL boronic ester vitrimers are in agreement with previously reported results for similar systems.…”

Section: Dmta and Rheological Analysesmentioning

confidence: 99%

On Sustainable Vitrimers Based on Polycaprolactones

Damonte,

Pellis,

Battegazzore

et al. 2024

ACS Appl. Polym. Mater.

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Vitrimers represent an environmentally friendly class of materials, which behave like thermosets at room temperature but exhibit thermoplastic flow behavior when heated, making them processable and recyclable, thus extending material life and reducing waste. However, to fully meet the current demand for a sustainable economy, biodegradability at the end of the material life should also be considered, a property that not all vitrimers possess. Based on the above issues, this work aimed to develop biodegradable vitrimers based on polycaprolactone (PCL), a biodegradable polyester potentially derived from biomass fermentation. In detail, three different ad hoc synthesized star-shaped acrylated PCLs, characterized by different number of arms and molecular weight, were synthesized and used to prepare vitrimeric systems. Indeed, the above polymers were cross-linked with a fast exchangeable diboronic ester dithiol (2,2′-(1,4-phenylene)-bis[4mercaptan-1,3,2-dioxaborolane], DBEDT), in solventless conditions. The formation of a dynamic network was proven by Fourier transform infrared, differential scanning calorimetry, thermogravimetric analysis, gel fraction, rheological, and dynamic mechanical analyzer measurements. In particular, the activation energies for the relaxation process of these materials were verified by rheological measurements in the range 44−62 kJ/mol. Moreover, all vitrimers, which were completely degraded by enzymatic hydrolysis within 12 days, exhibited excellent recyclability and self-healing properties when heated to 180 °C before processing.

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Section: Dmta and Rheological Analysesmentioning

confidence: 99%

On Sustainable Vitrimers Based on Polycaprolactones

Damonte,

Pellis,

Battegazzore

et al. 2024

ACS Appl. Polym. Mater.

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“…Recently, there has been a growing interest in the integration of DA reactions in polyurethane matrices [ 21 , 22 ]. This trend is mainly focused on the development of materials that are capable of performing self-healing processes [ 23 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Polyurethane Adhesives with Chemically Debondable Properties via Diels–Alder Bonds

Carbonell-Blasco,

Moyano,

Hernández-Fernández

et al. 2023

Polymers

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Covalent adaptable networks (CANs) represent a pioneering advance in polymer science, offering unprecedented versatility in materials design. Unlike conventional adhesives with irreversible bonds, CAN-based polyurethane adhesives have the unique ability to undergo chemical restructuring through reversible bonds. One of the strategies for incorporating these types of reactions in polyurethanes is by functionalisation with Diels–Alder (DA) adducts. By taking advantage of the reversible nature of the DA chemistry, the adhesive undergoes controlled crosslinking and decrosslinking processes, allowing for precise modulation of bond strength. This adaptability is critical in applications requiring reworkability or recyclability, as it allows for easy disassembly and reassembly of bonded components without compromising the integrity of the material. This study focuses on the sustainable synthesis and characterisation of a solvent-based polyurethane adhesive, obtained by functionalising a polyurethane prepolymer with DA diene and dienophiles. The characterisation of the adhesives was carried out using different experimental techniques: nuclear magnetic resonance spectroscopy (NMR), Brookfield viscosity, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and T-peel strength testing of leather/adhesive/rubber joints to determine the adhesive properties, both before and after the application of external stimuli. The conversion of both the DA and retro-Diels–Alder (r-DA) reactions was confirmed by 1H-NMR. The adhesive properties were not altered by the functionalisation of the adhesive prepolymer, showing similar thermal resistance and good rheological and adhesive properties, even exceeding the most demanding technical requirements for upper-to-sole joints in footwear. After the application of an external thermal stimuli, the bonded materials separated without difficulty and without damage, thus facilitating their separation, recovery and recycling.

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Phenoxy resin-based vinylogous urethane covalent adaptable networks

Cited by 2 publications

References 21 publications

On Sustainable Vitrimers Based on Polycaprolactones

On Sustainable Vitrimers Based on Polycaprolactones

Polyurethane Adhesives with Chemically Debondable Properties via Diels–Alder Bonds

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