Covalent Adaptable Networks with Associative Siloxane Exchange Enabled by Amide‐Based Internal Catalysis: Designing for Reprocessability and Extrudability by Increasing the Cross‐Link Density DOI Creative Commons
Nathan S. Purwanto, Tong Wang, Xiaoyang Liu

и другие.

Advanced Functional Materials, Год журнала: 2025, Номер unknown

Опубликована: Май 9, 2025

Abstract Replacing non‐recyclable thermosets with covalent adaptable networks (CANs) that recover cross‐link density after reprocessing will reduce waste and contribute to a circular polymer economy. Many CANs undergoing associative dynamic exchange require catalysis. External catalysis often leads harmful effects, e.g., increased creep, accelerated material aging, catalyst leaching. Herein, internally catalyzed siloxane chemistry is demonstrated resulting from amides covalently linked through alkyl chains siloxanes. Small‐molecule studies show the formation of products reaction two amide‐containing molecules. From rubbery plateau modulus, each siloxane‐exchange‐based CAN exhibits temperature‐invariant, or nearly so, characteristic CANs. The length in siloxane‐containing monomer tunes network density. Cross‐link recovery achieved, required time temperature decreasing increasing Stress relaxation also faster dynamics reprocessability arise because second order (i.e., cross‐linker) concentration. Capitalizing on this, melt extrusion highest demonstrated, achieving same extruded compression‐molded Using identical conditions, next‐highest not extrudable.

Язык: Английский

Reprocessable Polyurethane Foams Using Acetoacetyl-Formed Amides DOI
Hiba Kassem, Lucie Imbernon, Lucas Stricker

и другие.

ACS Applied Materials & Interfaces, Год журнала: 2023, Номер unknown

Опубликована: Ноя. 2, 2023

Like any other thermosetting material, polyurethane foams (PUFs) contain permanent cross-links that hinder their reprocessability and make recyclability a tedious environmentally unfriendly process. Herein, we introduce acetoacetyl-formed amides, formed by the reaction of isocyanates with acetoacetate groups, as dynamic units in backbone PUFs. By extensive variation foam composition, optimum parameters have been found to produce malleable above temperatures 130 °C, without requirement solvent during foaming The PU cross-linked material can be compression-molded at least three times, giving rise elastomers thus maintaining network structure. Characterization original shows comparable properties standard PUFs, for example, having density 32 kg/m3, while they show similar chemical thermal upon reprocessing strong elastomers, exhibiting Tg ranging from −42 −48 °C. This research provides straightforward method thermally reprocessable PUFs promising pathway address recycling issues end-of-life foams.

Язык: Английский

Процитировано

13
Facile Approach for the Preparation of Robust and Thermally Stable Silyl Ether Cross-Linked Poly(ethylene-vinyl acetate) Vitrimers DOI
Jincheng Zhang, Xiaopei Li, Songbo Zhang

и другие.

ACS Applied Polymer Materials, Год журнала: 2023, Номер 5(10), С. 8379 - 8386

Опубликована: Сен. 11, 2023

Vitrimers as an emerging class of dynamic polymer networks hold great promise for the development sustainable thermosets. While straightforward method to prepare vitrimers from commodity polymers is cost-competitive, most studies involved synthesis with specific functional groups and/or crosslinkers. Herein, we demonstrated a simple and scalable approach produce poly(ethylene-vinyl acetate) (EVA) by direct cross-linking industrial EVA product commercial bis[3-(trimethoxysilyl)propyl]amine using titanium(IV) butoxide catalyst through reactive blending. Incorporation thermally stable silyl ether cross-links into network led significantly enhanced thermal mechanical properties. Compared original EVA, resulting showed up 4 2 times improvement in Young's modulus tensile strength, respectively. The creep resistance vitrimer increased density, notably, EVA-V0.8 displayed low permanent deformation 1.2% at high temperature 180 °C, much higher than normal service temperature. Moreover, excellent reprocessability recyclability, modulus, elongation break were nearly identical even after four recycling.

Язык: Английский

Процитировано

12
Recycling of Polydicyclopentadiene Enabled with N‐Coordinated Boronic Ester Bonds DOI
Jiawei Hu, Yuan Gao,

Jianglu Teng

и другие.

Macromolecular Rapid Communications, Год журнала: 2024, Номер 45(16)

Опубликована: Май 9, 2024

In this contribution, the transformation of polydicyclopentadiene (PDCPD) from thermoset into vitrimer is introduced. First, two N-coordinated diboronic diols are successfully synthesized via reaction N,N,N-tri(2-hydroxyethyl)amine and/or N,N,N",N"-tetrakis(2-hydroxyethyl)ethylene diamine with 4-(hydroxymethyl) phenylboronic acid and then they transformed cyclic boronic diacrylates. The latter dienes carrying electron-withdrawing substituents used for ring opening insertion metathesis copolymerization (ROIMP) dicyclopentadiene to afford crosslinked PDCPD. PDCPD networks, ester bonds integrated. It found that as-obtained networks displayed excellent reprocessing properties. meantime, fracture toughness significantly improved. Owing inclusion bonds, modified PDCPDs have thermal stability much superior plain results reported in work demonstrate can be vitrimers introduction bonds.

Язык: Английский

Процитировано

5
Crosslinking of polyethylene with polysilsesquioxane via carbamate linkages: Synthesis, shape recovery, and reprocessing properties DOI
Jiawei Hu, Yuan Gao,

Guohua Hang

и другие.

Journal of Polymer Science, Год журнала: 2024, Номер 62(13), С. 2945 - 2960

Опубликована: Апрель 11, 2024

Abstract In this contribution, we reported the crosslinking of polyethylene (PE) with dynamic silyl ether bonds. First, polycyclooctene copolymers bearing hydroxyl groups were synthesized via ring‐opening metathesis copolymerization cyclooctene 5‐norbornene‐2‐methanol. The hydroxy‐functionalized further hydrogenated into corresponding PE copolymers. allowed to react 3‐isocyanatopropyltriethoxysilane obtain triethoxysilane groups. By taking advantage hydrolysis and condensation grafted onto chains, well crosslinked; polysilsesquioxane (PSSQ) segments behaved as linkages in networks. Notably, networks reprocessable (or recyclable) while zinc trifluoromethanesulfonate [Zn(OTf) 2 ] was incorporated. reprocessing properties quite dependent on densities. behavior is attributable introduction two chemistries: (i) bonds which catalyzed Zn(OTf) (ii) transcarbamoylation carbamates dibutyltin dilaurate. Owing crosslinking, displayed excellent shape memory properties. For networks, notably, original shapes can be reprogrammed aid exchange covalent introduced systems.

Язык: Английский

Процитировано

4
Trialkoxysilane Exchange: Scope, Mechanism, Cryptates and pH‐Response DOI Creative Commons
Selina Hollstein, Philipp Erdmann,

Andreas Ulmer

и другие.

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(26)

Опубликована: Апрель 28, 2023

Abstract The dynamic covalent chemistry (DCvC) of the Si−O bond holds unique opportunities, but has rarely been employed to assemble discrete molecular architectures. This may be due harsh conditions required initiate exchange reactions at silicon in aprotic solvents. Herein, we provide a comprehensive experimental and computational account on reaction trialkoxysilanes with alcohols identify mild for rapid Substituent, solvent salt effects are uncovered, understood exploited construction sila‐orthoester cryptates. A sharp, divergent pH‐response obtained cages renders this substance class attractive future applications well beyond host‐guest chemistry, instance, drug delivery.

Язык: Английский

Процитировано

9
Design of covalent adaptable networks with intrinsic flame retardancy DOI

Haoyuan Zu,

Zhishuai Geng,

Rongjie Yang

и другие.

Polymer Bulletin, Год журнала: 2024, Номер 81(12), С. 10489 - 10532

Опубликована: Март 29, 2024

Язык: Английский

Процитировано

3
Reaction of β‐Ketoester and 1,3‐Diol to Access Chemically Recyclable and Mechanically Robust Poly(vinyl alcohol) Thermosets through Incorporation of β‐(1,3‐dioxane)ester DOI Creative Commons
Youwei Ma, Chihui Zheng, Gadi Slor

и другие.

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(44)

Опубликована: Авг. 6, 2024

Abstract The development of mechanically robust, chemically stable, and yet recyclable polymers represents an essential undertaking in the context advancing a circular economy for plastics. Here, we introduce novel cleavable β‐(1,3‐dioxane)ester ( DXE ) linkage, synthesized through catalyst‐free reaction β‐ketoester 1,3‐diol, to cross‐link poly(vinyl alcohol) PVA formation high‐performance thermosets with inherent chemical recyclability. , modified groups transesterification excess tert ‐butyl acetoacetate, undergoes cross‐linking reactions unmodified 1,3‐diols within itself upon thermal treatment. architecture improves ’s mechanical properties, Young's modulus toughness that can reach up 656 MPa 84 MJ cm −3 i.e. approximately 3‐ 12‐fold those linear respectively. Thermal treatment cross‐linked under acid conditions leads deconstruction networks, enabling excellent recovery (>90 %) . In absence either or acidic treatment, maintains its dimensional stability. We show is also possible when performed presence other plastics commonly found recycling mixtures. Furthermore, ‐based composites comprising carbon fibers activated charcoal by linkages are shown be fillers.

Язык: Английский

Процитировано

3
Recyclable High-Performance Thermosetting Plastics from Isosorbide Based on Diels–Alder Reaction DOI
Jianjun Li, Weijun Yang, Pengwu Xu

и другие.

Industrial & Engineering Chemistry Research, Год журнала: 2025, Номер unknown

Опубликована: Март 19, 2025

Язык: Английский

Процитировано

0
Triple Effects of Fe3+ for the Integration of Mechanical Robustness, Reprocessability, and Unprecedented Thermal Stability into Polydimethylsiloxane DOI

Ronghao Li,

Junping Zheng

Macromolecules, Год журнала: 2025, Номер unknown

Опубликована: Март 25, 2025

Язык: Английский

Процитировано

0
Cleavable Strand‐Fusing Cross‐Linkers as Additives for Chemically Deconstructable Thermosets with Preserved Thermomechanical Properties DOI Creative Commons
Shu-yi Zhang, Zhenchuang Xu, Keith E. L. Husted

и другие.

Angewandte Chemie International Edition, Год журнала: 2025, Номер unknown

Опубликована: Март 27, 2025

Permanently cross-linked polymer networks-thermosets-are often difficult to chemically deconstruct. The installation of cleavable bonds into the strands thermosets using comonomers as additives can facilitate thermoset deconstruction without replacement permanent cross-links, but such monomers lead reduced thermomechanical properties and require high loadings function effectively, motivating design new optimal additives. Here, we introduce "strand-fusing cross-linkers" (SFCs), which fuse two network via a four-way cross-link. SFCs enable model polydicyclopentadiene (pDCPD) with little one-fifth molar loading needed achieve traditional comonomers. under oven curing well low-energy frontal ring-opening metathesis polymerization (FROMP) conditions improved properties, for example, glass transition temperatures, compared prior comonomer designs. This work motivates development increasingly compromising material performance.

Язык: Английский

Процитировано

0