Thermomechanical analysis (TMA) of vitrimers DOI Creative Commons
Amber M. Hubbard, Yixin Ren, Alireza S. Sarvestani

et al.

Polymer Testing, Journal Year: 2022, Volume and Issue: 118, P. 107877 - 107877

Published: Nov. 24, 2022

Vitrimers are an exciting class and new generation of polymer materials combining the strength a traditional thermoset with reprocessability thermoplastic polymer. However, key debate in literature has surrounded best method to identify vitrimer topology freezing temperature (Tv), above which dynamic covalent bond exchange reactions occur, allowing for self-healing, recycling, shape reconfigurability vitrimers. While common methods Tv include stress relaxation, creep, fluorescence, we herein validate thermomechanical analysis (TMA) as reliable identification. TMA provides several clear advantages it is less time sample intensive than relaxation. Furthermore, performed compression match application conditions, more consistent results identifies coefficient thermal expansion (α). We demonstrate that valuable tool identification by validating clearly accepted trends literature; validates increases decreasing catalyst concentration increasing heating rate while showing negligible variation applied force. Finally, report α our material. By taking advantage such fast Tv, believe this fundamental study will support future research.

Language: Английский

High-Performance Recyclable and Malleable Epoxy Resin with Vanillin-Based Hyperbranched Epoxy Resin Containing Dual Dynamic Bonds DOI

Yanxin Hao,

Liuyue Zhong,

Tingcheng Li

et al.

ACS Sustainable Chemistry & Engineering, Journal Year: 2023, Volume and Issue: 11(30), P. 11077 - 11087

Published: July 18, 2023

Dynamic covalent polymer networks represent new opportunities in the design of sustainable epoxy resins due to their excellent malleability and reprocessability; however, adaptable network is usually accompanied by low glass transition temperature, poor creep resistance, mechanical brittleness. Herein, we demonstrate a vanillin-based hyperbranched resin (VEHBP) containing disulfide imine dynamic bonds for recyclable malleable with high temperature (Tg), significantly improved properties. The 5%VEHBP exhibited 175 °C 130 34.1, 19.7, 173.3% increase tensile strength, storage modulus, toughness respectively, compared neat resin. Meanwhile, topological structure VEHBP complemented dual endowed these materials self-healing ability, reprocessability, degradability, which represents an important step toward fabrication high-performance networks.

Language: Английский

Citations

52

Molecular Dynamics Simulation and Theoretical Analysis of Structural Relaxation, Bond Exchange Dynamics, and Glass Transition in Vitrimers DOI
Tsai-Wei Lin, Baicheng Mei, Sarit Dutta

et al.

Macromolecules, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 30, 2025

Language: Английский

Citations

2

Reprocessable and Chemically Recyclable Hard Vitrimers Based on Liquid‐Crystalline Epoxides DOI
Thi En Trinh,

Kyosun Ku,

Hyeonuk Yeo

et al.

Advanced Materials, Journal Year: 2022, Volume and Issue: 35(11)

Published: Dec. 23, 2022

The rapid increase in demand for recyclable and reusable thermosets has necessitated the development of materials with chemical structures that exhibit these features. Thus, functional mesogenic epoxide monomers bearing both ester imine groups can be vitrimerized recycled are reported herein. compounds show mesophase characteristics at 100-200 °C converted into hard epoxides by a common curing reaction. obtained have high isotropic thermal conductivity (≈0.64 W m-1 K-1 ), which is derived from their highly ordered microstructures. cured products easily reprocessed through metathesis transesterification, decomposed hydrolysis under acidic or basic conditions subsequently re-cured. Surprisingly, repeatedly chemically decomposed. retain properties pristine counterparts, preserve advantages without alteration to any unique properties. A dehydration reaction occurs between residual hydroxyl during re-hardening, dramatically increases glass transition temperature ≈60 °C. These reprocessable vitrimers demonstrate effectiveness environmental friendliness molecular design strategy

Language: Английский

Citations

39

Structure, Dynamics, and Rheology of Vitrimers DOI
Jianshe Xia, Julia A. Kalow, Mónica Olvera de la Cruz

et al.

Macromolecules, Journal Year: 2023, Volume and Issue: 56(19), P. 8080 - 8093

Published: Sept. 29, 2023

Vitrimers are associative covalent adaptable networks that undergo reversible bond-exchange reactions while maintaining a fixed cross-linking density with changing temperature. To date, experimental studies rely on macroscopic rheology have not been able to reveal topological changes and microscopic dynamics in these materials. Here, coarse-grained molecular simulations combined Monte Carlo method implemented investigate the structural changes, dynamics, linear of unentangled side-chain-linked vitrimers conjunction sticky Rouse model (SRM). We find there is minor variation structure The dynamic heterogeneities behavior system increase remarkably when approaching freezing transition temperature Tv. Quantitative agreement between simulation results SRM predictions observed for stress relaxation, elastic loss moduli, relative mean-squared displacement, especially at intermediate- long-time or low-frequency regimes, where time–temperature superposition principle satisfied. obtain scaling collapse curve bond relaxation time, zero-shear viscosity, horizontal shift factors without introducing any parameters, suggesting exhibit similar even presence loop defects. Moreover, good those predicted by SRM, indicating fast rate can be analyzed via single-chain approach based SRM.

Language: Английский

Citations

27

Reformable and sustainable thermosetting carbon fiber composites from epoxy vitrimer DOI Creative Commons
Philip R. Barnett, Justin A. Brackenridge, Abigail A. Advincula

et al.

Composites Part B Engineering, Journal Year: 2024, Volume and Issue: 274, P. 111270 - 111270

Published: Feb. 7, 2024

Language: Английский

Citations

14

Self-Consistent Theory for Structural Relaxation, Dynamic Bond Exchange Times, and the Glass Transition in Polymeric Vitrimers DOI
Baicheng Mei, Christopher M. Evans, Kenneth S. Schweizer

et al.

Macromolecules, Journal Year: 2024, Volume and Issue: 57(7), P. 3242 - 3257

Published: March 28, 2024

We formulate a statistical mechanical theory for how dynamic bond exchange influences the activated hopping-driven relaxation of Kuhn segments in dynamically cross-linked networks or vitrimers over wide range temperatures and cross-link densities. The key new methodological aspect is to address self-consistent manner consequences on segmental alpha relaxation, vice versa. predicted temperature dependence time at high remains same as that permanent networks, but lower temperatures, significant acceleration occurs due exchanges. From mechanistic perspective, vitrimer local cage barrier very weakly affected by exchange, while collective elastic contribution decreases significantly deeply supercooled regime. glass transition grow linearly with square root density, previously found networks. Material-specific chemical effects such cross-linker size relative normal segment special attraction polymers are crudely considered based model calculations. quantitatively applied recent experiments dry ethylene vitrimers. Good agreements including follows an Arrhenius law enough upward non-Arrhenius deviations emerge regime, collapsed master curve exists densities temperatures. Possible extensions treat heterogeneity penetrant transport briefly discussed.

Language: Английский

Citations

13

Ultra‐high Performance Thermochromic Polymers via a Solid‐solid Phase Transition Mechanism and Their Applications DOI
Xiang Yun Debbie Soo, Danwei Zhang, Sze Yu Tan

et al.

Advanced Materials, Journal Year: 2024, Volume and Issue: unknown

Published: June 25, 2024

Thermochromic materials are substances that change color in response to temperature variations. Today, sustainability concerns the main drivers of thermochromic research, with smart, energy-efficient windows being one primary applications. While vanadium oxides and leuco dyes traditionally materials, hydrogels operating based on solvation have risen as some most promising due their high optical transparency good solar modulating abilities. In this work, a distinct mechanism for thermochromism arising from crystalline solid amorphous polymer transition, corresponding transition an opaque state transparent is disclosed. Both ultra-high (T

Language: Английский

Citations

12

Temperature-Dependent Fracture Toughness of Epoxy Vitrimers DOI

Yuxiang Sun,

Xudong Wang, Yi Zhao

et al.

Macromolecules, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Vitrimer, a class of covalent dynamic networks, is promising for polymeric applications requiring reshaping, recycling, and self-healing. The bonds in vitrimer can be reversibly broken reformed under thermal actuation. This work investigates the effects temperature on fracture toughness soft epoxy vitrimers. We measured above topology freezing temperature. Elevated temperatures reduce both stretch toughness, while they linearly increase modulus. Given invariant cross-linking density, dependence attributed to sensitivity bond-exchange reactions. extend Lake–Thomas theory by incorporating kinetic bond scission elucidate such Unlike conventional elastomers with threshold decreased at elevated temperatures, our indicates continuous decrease until approximating zero value, aligning unique viscous behavior

Language: Английский

Citations

1

Predicting delayed stability of metals at constant high temperatures DOI

Jinlai Zhou,

Bo Peng, Qing Yao

et al.

Materials Science and Engineering A, Journal Year: 2025, Volume and Issue: unknown, P. 148163 - 148163

Published: March 1, 2025

Language: Английский

Citations

1

Linear Viscoelasticity of Polystyrene Vitrimers: Segmental Motions and the Slow Arrhenius Process DOI
Daniel Barzycki, Dana Ezzeddine, Sachin Shanbhag

et al.

Macromolecules, Journal Year: 2025, Volume and Issue: unknown

Published: April 4, 2025

Language: Английский

Citations

1