Biobased polyurethane coatings with fast self-healing and tunable mechanical properties derived from curcumin and castor oil

Progress in Organic Coatings, Год журнала: 2023, Номер 183, С. 107816 - 107816

Опубликована: Июль 20, 2023

Язык: Английский

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Polybenzoxazine-based covalent adaptable networks: A mini-review

Polymer, Год журнала: 2023, Номер 287, С. 126426 - 126426

Опубликована: Окт. 25, 2023

Benzoxazines represent a class of thermoset resins known for their exceptional thermal, fire, and mechanical properties. These find wide applications in various industries, including composites electronic components. However, like conventional thermosets, benzoxazines have limitations terms end-of-life options, typically being landfilled or incinerated. To address this concern, researchers been exploring the incorporation dynamic bonds into structure polybenzoxazines to add functionalities such as reprocessability, self-healing, recycling capabilities, develop polybenzoxazine-based covalent adaptable networks (CANs). This mini-review offers an overview recent endeavors focused on introduction within polybenzoxazine structures. It emphasizes synergies between molecular exchanges, transesterification disulfide metathesis, provides comparative summary properties achieved by materials developed context. By leveraging strengths benzoxazine structures, aims foster exploration development innovative approaches that combine unique CANs, enabling more sustainable environmentally friendly materials.

Язык: Английский

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Deciphering Siloxane Bond Exchanges: From a Molecular Study to Vitrimerization and Recycling of Silicone Elastomers

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(12)

Опубликована: Янв. 25, 2023

The activity of various additives promoting siloxane equilibration reactions is examined and quantified on model compounds. We found in particular that the "superbase" phosphazene derivative P4 -t Bu can promote very fast exchanges (a few seconds at 90 °C) even low concentration (<0.1 wt %). demonstrate permanent silicone networks be transformed into reprocessable recyclable dynamic by mere introduction such additives. Annealing high temperature degrades deactivates features networks, reverting them back networks. A simple rheological experiment corresponding allow to extract critical kinetic parameters predict control deactivations.

Язык: Английский

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Green Catalysts for Reprocessing Thermoset Polyurethanes

Macromolecules, Год журнала: 2023, Номер 56(17), С. 6978 - 6987

Опубликована: Авг. 27, 2023

Polyurethane (PU) thermosets are usually landfilled at the end of their service lifetimes and cannot be recycled through conventional means. Although dibutyltin dilaurate (DBTDL) is an effective catalyst for reprocessing PU thermosets, organotins immunotoxic teratogenic, which concerning catalysts embedded within covalent adaptable networks (CANs). Here, we identify Zr(acac)4 Zr(tmhd)4 as to reprocess CANs more sustainably. Thermoset foams containing Zr-based exhibit characteristic stress relaxation times between 6 200 s, similar or faster than DBTDL. These capable a foam four five cycles. Dynamic mechanical thermal analysis indicates that zirconium-based preserve glass transition temperature crosslink density cycles promising bulk thermoset PUs. Furthermore, solvent-free method was developed by co-milling Zr catalyst. Ultimately, these methods using will impart greater sustainability circularity plastics.

Язык: Английский

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Thermally Robust yet Deconstructable and Chemically Recyclable High‐Density Polyethylene (HDPE)‐Like Materials Based on Si−O Bonds

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(51)

Опубликована: Окт. 30, 2023

Polyethylene (PE) is the most widely produced synthetic polymer. By installing chemically cleavable bonds into backbone of PE, it possible to produce deconstructable PE derivatives; date, however, such designs have primarily relied on carbonyl- and olefin-related functional groups. Bifunctional silyl ethers (BSEs; SiR2 (OR'2 )) could expand scope mimics as they possess strong Si-O facile chemical tunability. Here, we report BSE-containing high-density polyethylene (HDPE)-like materials synthesized through a one-pot catalytic ring-opening metathesis polymerization (ROMP) hydrogenation sequence. The crystallinity these can be adjusted by varying BSE concentration or steric bulk Si-substituents, providing handles control thermomechanical properties. Two methods for recycling HDPE are introduced, including circular approach that leverages acid-catalyzed bond exchange with 1-propanol. Additionally, despite fact starting were chain-growth (ROMP), show recover molar mass dispersity recycled products using step-growth formation exchange, generating high molecular weight mechanical properties similar commercial HDPE.

Язык: Английский

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