Non-isocyanate Polythiourethane Network from Biowaste: Achieving Circularity via Multidimensional Chemical Recycling with Valuable Small-Molecule Recovery and Reprocessability by Understanding the Dynamic Chemistry

Macromolecules, Год журнала: 2023, Номер 57(2), С. 490 - 502

Опубликована: Дек. 29, 2023

We studied and established the dual nature of non-isocyanate polythiourethane (NIPTU) dynamic chemistry capitalized on our understanding to achieve multidimensional chemical recycling a cross-linked NIPTU, also known as poly(mercapto-thiourethane). This NIPTU includes first demonstration recovery valuable small molecules in addition reprocessability with full cross-link density recovery. In particular, we performed investigation using small-molecule analogues. identified two types chemistry: reversible cyclic thiocarbonate aminolysis, where thiourethane (NITU) groups reversibly dissociate into thiocarbonates amines, trans(thio)carbamoylation, thionourethane linkages within NITU undergo exchange reactions alcohol. synthesized renewable glycerol-based (GNIPTU) high biowaste-derivable content. Capitalizing recovered pure di(thiocarbamate) 94 mol % yield, one highest yields among reported studies polymers. The GNIPTU network exhibited property after reprocessing, providing another effective method recycling. With robust properties, content, capability excellent recovery, reprocessability, exemplifies how low-cost, renewable, polyurethane-like materials can be developed both high-performance characteristics potential contribute meaningfully polymer circularity.

Язык: Английский

---

3D Printing of continuous fiber composites using two-stage UV curable resin

Materials Horizons, Год журнала: 2023, Номер 10(12), С. 5508 - 5520

Опубликована: Янв. 1, 2023

3D printing allows for moldless fabrication of continuous fiber composites with high design freedom and low manufacturing cost per part, which makes it particularly well-suited rapid prototyping composite product development. Compared to thermal-curable resins, UV-curable resins enable the content faster speeds. However, printed exhibit mechanical strength weak interfacial bonding high-performance engineering applications. In addition, they are typically not reprocessable or repairable; if could be, would dramatically benefit products improved durability, reliability, savings, streamlined workflow. this study, we demonstrate that recently emerged two-stage resin is an ideal material candidate tackle these grand challenges in thermoset carbon fiber. The consists primarily acrylate monomers crosslinkers exchangeable covalent bonds. During process, filaments containing up 30.9% can be rapidly deposited solidified through UV irradiation. After printing, subjected post-heating. Their stiffness, strength, inter-filament significantly enhanced due bond exchange reactions within matrix. Furthermore, utilization curable enables repair, reshaping, recycling thermosetting composites. This study represents first detailed explore benefits using printing. fundamental understanding potentially extended other types different molecular mechanisms.

Язык: Английский

---

Closed‐Loop Recyclable Poly(ester‐disulfide)s for Potential Alternatives to Engineering Plastic

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(38)

Опубликована: Июнь 21, 2024

Facile fabrication, low material complexity and closed-loop recycling are essential for polymer plastics to alter their linear product economy towards a cradle-to-cradle one. Covalent adaptable networks (CANs) one way achieve that, which intrinsically exhibit decent mechanical properties like the thermosets but could also be easily recycled thermoplastics. In this work, we introduce rigid ester structural motifs into dynamic poly(disulfide)s form series of dual networks. Owning coherence soft/rigid segments reversible sacrificial crosslinking, they tailorable good resistance different chemicals. Their is achieved via mild solvolysis, maintaining materials' integrities. It offers solution as sustainable replacement engineering massively under production hard recycled.

Язык: Английский

---

Dynamic Entwined Topology in Helical Covalent Polymers Dictated by Competing Supramolecular Interactions

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(20)

Опубликована: Март 6, 2024

Abstract Naturally occurring polymeric structures often consist of 1D polymer chains intricately folded and entwined through non‐covalent bonds, adopting precise topologies crucial for their functionality. The exploration crystalline polymers dynamic covalent chemistry (DCvC) supramolecular interactions represents a novel approach developing polymers. This study shows that sub‐angstrom differences in the counter‐ion size can lead to various helical (HCP) topologies, including metal‐coordination HCP (m‐HCP) motif. Single‐crystal X‐ray diffraction (SCXRD) analysis HCP−Na revealed double pairs are formed by sodium ions coordinating spiroborate linkages form rectangular pores. helices interpenetrated unreacted diols ions. reticulation m‐HCP structure was demonstrated successful synthesis HCP−K. Finally, ion‐exchange studies were conducted show interconversion between structures. research illustrates how seemingly simple modifications, such as changes size, significantly influence topology determine which dominate crystal lattice.

Язык: Английский

---

Catalyst‐Free Dynamic Covalent C=C/C=N Metathesis Reaction for Associative Covalent Adaptable Networks

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Июнь 3, 2024

Covalent adaptable networks (CANs), leveraging the dynamic exchange of covalent bonds, emerge as a promising material to address challenge irreversible cross-linking in thermosetting polymers. In this work, we explore introduction catalyst-free and associative C=C/C=N metathesis reaction into polyurethanes, creating CANs with superior stability, solvent resistance, thermal/mechanical properties. By incorporating reaction, stress-relaxation is significantly accelerated compared imine-bond-only networks, rate adjustable by modifying substituents ortho position double bonds. The obtained plasticity enables recycle without altering chemical structure or mechanical properties, also found be vital for achieving shape memory functions complex spatial structures. This new crosslinker polymer has potential accelerate ongoing exploration malleable functional thermoset

Язык: Английский

---

Covalent Adaptable Networks Containing Nitrogen-Coordinated Boronic Ester and Imine Bonds

ACS Applied Polymer Materials, Год журнала: 2024, Номер 6(15), С. 9008 - 9016

Опубликована: Июль 31, 2024

Covalent adaptable networks (CANs) are supposed to address the reprocessing and recycling issues of epoxy resins via their reversible cross-linking structures. However, development CANs simultaneously exhibiting high mechanical strength fast-reprocessing ability is still a huge challenge. Herein, with fabricated by modifying linear polymers nitrogen-coordinated boronic ester imine bonds. Owing densities rigid network structures, obtained show breaking ∼76.0 MPa, yield stress ∼81.5 Young's modulus ∼1.67 GPa, respectively. Because fast exchange reaction bonds, as-prepared can be easily processed into desirable shapes within only 1 min at 150 °C under pressure 10 MPa. Moreover, owing this unique feature, quickly reprocessed least three times without losing original properties. Finally, prepared exhibit shape fixed ratio recovery more than ∼90% when used as shape-memory polymers. This study provides feasible solution for constructing mechanically strong thermosets ability, which will contribute next-generation sustainable resins.

Язык: Английский

---

3D interfacial material-locking structures to promote bonding strength of dissimilar materials

Journal of Manufacturing Processes, Год журнала: 2024, Номер 112, С. 92 - 102

Опубликована: Янв. 21, 2024

Язык: Английский

---

Ultra‐Fast Selenol‐Yne Click (SYC) Reaction Enables Poly(selenoacetal) Covalent Adaptable Network Formation

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Авг. 14, 2024

The emergence of covalent adaptable networks (CANs) based on dynamic bonds (DCBs) presents a promising avenue for achieving resource recovery and utilization. In this study, we discovered bond called selenacetal, which is obtained through double click reaction between selenol activated alkynes. Density functional theory (DFT) calculations demonstrated that the ΔG formation selenoacetals ranges from 12 to 18 kJ mol

Язык: Английский

---

Covalent adaptable polymer networks with CO2-facilitated recyclability

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Авг. 4, 2024

Cross-linked polymers with covalent adaptable networks (CANs) can be reprocessed under external stimuli owing to the exchangeability of dynamic bonds. Optimization reprocessing conditions is critical since increasing temperature costs more energy and even deteriorates materials, while reducing via molecular design usually narrows service range. Exploiting CO2 gas as an trigger for lowering barrier shows great promise in low sample contamination environmental friendliness. Herein, we develop a type CANs incorporated ionic clusters that achieve CO2-facilitated recyclability without sacrificing performance. The presence facilitate rearrangement clusters, thus promoting exchange effective stress relaxation network enable system rapid recycling retaining excellent mechanical performance working conditions. This work opens avenues recyclable polymer materials tunable dynamics responsive recyclability. are at high temperatures which might deteriorate their Here, authors introduce carbon dioxide into bonds providing good

Язык: Английский

---

Dual‐Factor‐Controlled Dynamic Precursors Enable On‐Demand Thermoset Degradation and Recycling

Advanced Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 3, 2024

Abstract Thermosets are well known for their advantages such as high stability and chemical resistance. However, developing sustainable thermosets with degradability recyclability faces several principal challenges, including reconciling the desired characteristics during service recycling reprocessing properties required at end of life, establishing efficient methods large‐scale synthesis, aligning current manufacturing process. Here a general strategy is presented on‐demand degradation under mild conditions utilizing dynamic precursors dual‐factor‐controlled reversibility. Specifically, triazine crosslinkers introduced through nucleophilic aromatic substitution (S N Ar) into precursor polyols used in polyurethane (PU) synthesis. Upon removal catalyst alcohol, reversibility S Ar deactivated, allowing use standard PU polymerization techniques injection molding, casting, foaming. The resulting cyanurate‐crosslinked PUs maintain diverse mechanical traditional crosslinked PUs, yet offer advantage easy depolymerization by activating specific but conditions—a combination base, heat. It envisioned that this approach, involving pre‐installation crosslinkers, can be broadly applied to thermosetting plastic processes, introducing enhanced sustainability.

Язык: Английский

---