Covalent Adaptable Networks and Thermosets of Multi-block Ethylene/1-Octene Copolymers Made by Free-Radical Processing: Effects of Melt Flow Index and Crystallinity on Thermomechanical Properties and Reprocessability DOI
Logan M. Fenimore, Boran Chen, Yixuan Chen

и другие.

SSRN Electronic Journal, Год журнала: 2023, Номер unknown

Опубликована: Янв. 1, 2023

Chain shuttling polymerization has facilitated the rapid development of olefin block copolymers (OBCs) such as ethylene/1-octene multi-block copolymers. The properties OBCs stem from various parameters average length, number blocks per chain, etc., which lead to complexity associated with establishing structure-property relationships between precursor and cross-linked OBCs. Additionally, permanent cross-linking sacrifices their recyclability, capable being reprocessed have seldom been reported. Here, permanently (OBCXs) dynamically OBCs, or OBC covalent adaptable networks (CANs), were synthesized by melt-state reactive processing neat crystallinities melt flow indices (MFIs). CANs are dialkylamino disulfide dynamic chemistry via grafting bis(2,2,6,6-tetramethyl-4-piperidyl methacrylate) disulfide, BiTEMPS methacrylate, cross-linkers onto backbone chains. Thermomechanical characterizations indicate that increasing crystallinity decreasing MFI in higher cross-link densities OBCXs CANs. Dynamically into also significantly improves elevated-temperature creep resistance. Stress relaxation results an increased time greater density. Distinct other chemistry, stress behaviors density show evident dependence on network viscoelasticities. In lower density, more strongly governs behaviors. Finally, exhibit full thermomechanical property recovery after reprocessing, whereas cannot be due irreversible cross-links.

Язык: Английский

New Advances in Covalent Network Polymers via Dynamic Covalent Chemistry DOI
Zepeng Lei, Hongxuan Chen, Shaofeng Huang

и другие.

Chemical Reviews, Год журнала: 2024, Номер 124(12), С. 7829 - 7906

Опубликована: Июнь 3, 2024

Covalent network polymers, as materials composed of atoms interconnected by covalent bonds in a continuous network, are known for their thermal and chemical stability. Over the past two decades, these have undergone significant transformations, gaining properties such malleability, environmental responsiveness, recyclability, crystallinity, customizable porosity, enabled development integration dynamic chemistry (DCvC). In this review, we explore innovative realm polymers focusing on recent advances achieved through application DCvC. We start examining history fundamental principles DCvC, detailing its inception core concepts noting key role reversible bond formation. Then reprocessability DCvC is thoroughly discussed, starting from milestones that marked evolution progressing to current trends applications. The influence crystallinity then reviewed, covering diversity, synthesis techniques, functionalities. concluding section, address challenges faced field speculates potential future directions.

Язык: Английский

Процитировано

58
Biobased, reprocessable, self-blown non-isocyanate polyurethane foams: Influence of blowing agent structure and functionality DOI Creative Commons
Nathan S. Purwanto, Yixuan Chen, John M. Torkelson

и другие.

European Polymer Journal, Год журнала: 2024, Номер 206, С. 112775 - 112775

Опубликована: Янв. 19, 2024

Язык: Английский

Процитировано

15
Covalent Adaptable Networks Made by Reactive Processing of Highly Entangled Polymer: Synthesis-Structure-Thermomechanical Property-Reprocessing Relationship in Covalent Adaptable Networks DOI
Logan M. Fenimore, Mathew Suazo, John M. Torkelson

и другие.

Macromolecules, Год журнала: 2024, Номер 57(6), С. 2756 - 2772

Опубликована: Март 6, 2024

Reactive processing provides a simple approach for grafting dynamic covalent cross-linkers onto linear or branched polymers, resulting in adaptable networks (CANs). We synthesized poly(n-hexyl methacrylate) (PHMA) CANs from neat, entangled PHMA using radical-based reactive to graft the cross-linker called BiTEMPS methacrylate (BTMA) between side chains. By tuning BTMA loading, we achieved range of cross-link densities and characterized how stress relaxation, elevated-temperature creep, reprocessability are affected by density. The cross-links chains allowed novel comparison our reversible, polymers described sticky reptation theory, which long-time relaxation occurs unraveling backbone entanglements, process enabled dissociation subsequent exchange side-chain "stickers." observed two regimes that required their fitting combination stretched exponential decay functions extract pertinent parameters. apparent activation energies creep viscosity same within experimental uncertainty these CANs, verifying shared mechanisms governing temperature dependence viscoelastic responses, independent CAN Notably, made linking ∼50–60% those reported previously with chain backbones. These outcomes demonstrate importance synthesis-structure-property-reprocessing relationships may be various methods varying position incorporation structure.

Язык: Английский

Процитировано

15
Polypropylene Covalent Adaptable Networks with Full Cross-Link Density Recovery after Reprocessing: Development by Free-Radical Reactive Processing with Resonance-Stabilized, Aromatic Disulfide Cross-Linkers DOI
Yen-Wen Huang, Mathew Suazo, Stephanie M. Barbon

и другие.

ACS Macro Letters, Год журнала: 2025, Номер unknown, С. 341 - 348

Опубликована: Март 5, 2025

A single-step method that produces percolated, dynamic covalent cross-links integrated into the PP homopolymer has not been previously demonstrated. Here, we synthesized adaptable networks (CANs) from polypropylene (PP) homopolymers using 180 °C, radical-based, reactive processing with a free-radical initiator, dicumyl peroxide (DCP), and resonance-stabilized, aromatic disulfide cross-linkers, one methacrylate-based another phenyl acrylate-based. Both cross-linkers yielded when reactively processed at 4 wt % relatively high molecular weight (MW) (melt flow index (MFI) = 12) DCP. The acrylate-based cross-linker also other studied DCP/cross-linker concentrations low MW (MFI 35). Notably, our highest cross-link density CAN exhibited full recovery of after three reprocessing steps by compression molding; within experimental uncertainty melt extrusion.

Язык: Английский

Процитировано

2
BiTEMPS methacrylate dynamic covalent cross-linker providing rapid reprocessability and extrudability of covalent adaptable networks: high-yield synthesis with strong selectivity for disulfide linkages DOI Creative Commons
Tapas Debsharma, Nathan S. Purwanto, Logan M. Fenimore

и другие.

Polymer Chemistry, Год журнала: 2024, Номер 15(21), С. 2167 - 2176

Опубликована: Янв. 1, 2024

A dialkylamino disulfide-based dynamic covalent cross-linker (BTMA) was synthesized with high purity and selectivity for disulfides used to produce rapidly reprocessable extrudable adaptable networks n -hexyl methacrylate.

Язык: Английский

Процитировано

6
Increasing the cross-link density in a dual dissociative and associative polythiourethane covalent adaptable network improves both creep resistance and extrudability DOI
Sergio Serna, Nathan S. Purwanto, Logan M. Fenimore

и другие.

Polymer, Год журнала: 2024, Номер 306, С. 127232 - 127232

Опубликована: Июнь 1, 2024

Язык: Английский

Процитировано

6
Direct and Reversible Transformations between Intermolecular Polymer Networks and Single-Chain Nanoparticles Based on Thermally Dissociable Bis(hindered amino)disulfide Linkages DOI

Gota Tomono,

Hirogi Yokochi, Akira Takahashi

и другие.

Macromolecules, Год журнала: 2024, Номер 57(13), С. 6362 - 6369

Опубликована: Июнь 27, 2024

We report a direct topological reorganization between intermolecularly cross-linked polymers and single-chain nanoparticles (SCNPs) via thermal exchange reactions based on bis(2,2,6,6-tetramethylpiperidin-1-yl)disulfide (BiTEMPS) linkages. The network architecture of poly(hexyl methacrylate) incorporating BiTEMPS at the cross-linking points can be directly transformed to SCNPs merely by heating in dilute solution. Diffusion-ordered NMR spectroscopy GPC analyses confirmed smaller hydrodynamic radii compared those chain obtained de-cross-linking original networks. reverse transformation from polymer networks was achieved simply under solvent-free conditions. Time-course monitoring storage moduli showed clear increase as function time due restoration intermolecular cross-links disulfide-exchange reactions. restored exhibited comparable densities mechanical properties polymers, were again replicated well after an additional network–SCNP cycle. Such on-demand network-modulation feature enables postsynthetic adjustment elastomer by, e.g., fusing prepared with different densities.

Язык: Английский

Процитировано

5
Rapidly Self‐Healable and Melt‐Extrudable Polyethylene Reprocessable Network Enabled with Dialkylamino Disulfide Dynamic Chemistry DOI Creative Commons
Boran Chen, Tapas Debsharma, Logan M. Fenimore

и другие.

Macromolecular Rapid Communications, Год журнала: 2024, Номер 45(22)

Опубликована: Июль 24, 2024

Abstract Catalyst‐free, radical‐based reactive processing is used to transform low‐density polyethylene (LDPE) into covalent adaptable networks (PE CANs) using a dialkylamino disulfide crosslinker, BiTEMPS methacrylate (BTMA). Two versions of BTMA are used, BTMA‐S 2 , with nearly exclusively bridges, and n mixture oligosulfide produce S PE CAN CAN, respectively. The two CANs exhibit identical crosslink densities, but the manifests faster stress relaxation, average relaxation times ∼4.5 shorter than those over 130 160 °C temperature range. more rapid dynamics translate compression‐molding reprocessing time at only 5 min (vs 30 for CAN) achieve full recovery density. Both melt‐extrudable within experimental uncertainty density after extrusion. self‐healable, crack fully repaired original tensile properties restored or 60 slightly above LDPE melting point without assistance external forces.

Язык: Английский

Процитировано

5
Covalent adaptable networks and thermosets of multi-block ethylene/1-octene copolymers made by free-radical processing: Effects of melt flow index and crystallinity on thermomechanical properties and reprocessability DOI Open Access
Logan M. Fenimore, Boran Chen, Yixuan Chen

и другие.

European Polymer Journal, Год журнала: 2023, Номер 202, С. 112661 - 112661

Опубликована: Дек. 5, 2023

Язык: Английский

Процитировано

10
Reprocessable, Self-Healing, and Creep-Resistant Covalent Adaptable Network Made from Chain-Growth Monomers with Dynamic Covalent Thionourethane and Disulfide Cross-Links DOI
Tong Wang, Yixuan Chen, Boran Chen

и другие.

ACS Macro Letters, Год журнала: 2024, Номер 13(9), С. 1147 - 1155

Опубликована: Авг. 16, 2024

We synthesized covalent adaptable networks (CANs) made from chain-growth comonomers using nonisocyanate thiourethane chemistry. derivatized glycidyl methacrylate with cyclic dithiocarbonate (GMA-DTC), did a free-radical polymerization of n-hexyl GMA-DTC to obtain statistical copolymer 8 mol % GMA-DTC, and cross-linked it difunctional amine. The dynamic thionourethane disulfide bonds lead CAN reprocessability full recovery the cross-link density; temperature dependence rubbery plateau modulus indicates that associative character dominates response. exhibits complete self-healing at 110 °C tensile property excellent creep resistance 90–100 °C. Stress relaxation 140–170 reveals an activation energy 105 ± 6 kJ/mol, equal (Ea) poly(n-hexyl methacrylate) backbone α-relaxation. hypothesize CANs exclusively or predominantly dynamics have their stress-relaxation Ea defined by α-relaxation Ea. This hypothesis is supported stress studies on similar poly(n-lauryl methacrylate)-based CAN.

Язык: Английский

Процитировано

4