Manipulating the mechanical properties of cis-polyisoprene nanocomposites via molecular dynamics simulation

Chen, Qionghai; Huang, Wanhui; Duan, Pengwei; Yue, Tongkui; Zhang, Liqun; Wu, Xiaohui; Li, Jun

doi:10.1016/j.polymer.2022.125233

Cited by 18 publications

(13 citation statements)

References 45 publications

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“…A uniaxial stretching protocol follows our previous studies. ,, We adopt a fixed engineering strain rate to change the size of the simulated box in the Z -axis direction and simultaneously reduce the size in the X -axis and Y -axis directions to ensure the volume of the simulated box remains unchanged. The strain rate is as follows where L Z ( t ) and L Z (0) represent the length of the simulated box in the Z -axis direction at time t and the initial time, respectively.…”

Section: Models and Methodsmentioning

confidence: 99%

“…Polymer nanocomposites (PNCs) are used in various fields, and the introduced nanoparticles (NPs) bring unique properties, including thermal conductivity, − electrical conductivity, and mechanical properties. , Some nanofillers, such as carbon nanotubes (CNTs), have a much lower mechanical enhancement of PNCs than theoretical predictions . Numerous experimental and theoretical studies have been carried out to investigate the dispersion − and orientation − of nanofillers to address their impact on the mechanical properties of PNCs. Manipulation of the orientation of nanoparticles (NPs) in PNCs has been achieved by in situ polymerization, , applying an electric field or magnetic field, , and simply stretching or shearing , PNCs.…”

Section: Introductionmentioning

confidence: 99%

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Insights into Uniaxial Tension and Relaxation of Nanorod-Filled Polymer Vitrimer Nanocomposites: A Molecular Dynamics Simulation

et al. 2023

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The mechanical properties of polymer nanocomposites (PNCs) depend sensitively on the structure (e.g., orientation, dispersion, and so on) of the incorporated nanofillers. Many studies have shown that the alignment of anisotropic nanofillers can improve the mechanical properties of PNCs. However, achieving this alignment typically requires complex preparation processes. To address this challenge, researchers have introduced dynamic covalent bonds to form reversible cross-linked polymer systems, which would lead to unique properties, such as self-healing, recyclability, and reprocessibility. In addition, inspired by the above ideas, we introduce nanorods as fillers into a linear vitrimer system to form nanorod vitrimer composites (NVCs). In NVCs, we can easily manipulate the alignment of the nanorods due to bond exchange reactions (BERs) in the vitrimer matrices. By using coarse-grained molecular dynamics (CGMD) simulations, we systematically investigate the factors affecting the nanorod orientation in NVCs. We find that the main factor affecting the nanorod orientation is the network rearrangement caused by BERs. Specifically, the BER potential barrier (ΔE sw) directly determines the probability of BERs’ occurrence. At the same time, the increase of the interfacial interaction between polymer chains and nanorods (εnp) confines the motion of the active beads, which slows down the rate of BERs. Additionally, the impact of temperature (T) and aspect ratio (ld) on the orientation of nanorods during uniaxial stretching or stress relaxation are also discussed. Finally, by combining uniaxial stretching and stress relaxation processes, we elucidate the orientation retention mechanism of NVCs and demonstrate the mechanical property enhancement phenomenon of the pre-oriented NVC systems. This work provides a simple strategy for manipulating the nanorod alignment in vitrimer matrices and uncovers guidelines for designing new functional polymer vitrimer nanocomposites at the molecular level.

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Section: Models and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Insights into Uniaxial Tension and Relaxation of Nanorod-Filled Polymer Vitrimer Nanocomposites: A Molecular Dynamics Simulation

et al. 2023

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“…6,35 In our simulation, each polymer chain consists of 100 beads with a mass equal to m, and the diameter was equal to σ , which was considered a reasonable parameter for the CGMD simulation. As the chain length in our simulation was longer than the critical entanglement length ( N e ≈ 35), 34,36–39 our study should be considered as being representative of entangled systems.…”

Section: Models and Methodsmentioning

confidence: 99%

“…The value of the interaction strength ( ξ ) was about 2.5–4.2 kJ mol −1 for the different polymers when mapping the bead-spring model to the natural polymers. 39 For a better comparison, all the force-field parameters are listed in Table 1. The LJ potential was cut at different distances to simulate attractive or repulsive interactions.…”

Section: Models and Methodsmentioning

confidence: 99%

Molecular dynamics simulation of the impact of the surface topology of carbon black on the mechanical properties of elastomer nanocomposites

Zhang

Fang

Chen

et al. 2023

Phys. Chem. Chem. Phys.

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“…When heated to a certain temperature, it can easily dissociate into isocyanate groups and oxime groups, and simultaneously also reform the oxime–carbamate bond. − Therefore, dynamic oxime–carbamate bonds are introduced into the polymer network to prepare elastomers with excellent self-healing properties. , However, the self-healing behavior and mechanisms of polyurethane based on dynamic oxime–carbamate bonds at the molecular level are not well understood. Our previous works have demonstrated the applicability of molecular dynamics (MD) simulations to study the dynamic and static mechanical properties of elastomers and to reveal their intrinsic mechanisms. − To date, although a large number of experimental studies have successfully designed and prepared elastomers with excellent self-healing ability, there are very few self-healing elastomers based on dynamic covalent bonds analyzed by a combination of experiments and MD simulations . In contrast to experiments, MD simulations have been used extensively to study the self-healing behavior and mechanisms of polymer networks at the molecular level. − To further improve the design and optimization of self-healing polymer networks, it is important to clarify the self-healing behavior and mechanisms at the molecular level. , …”

Section: Introductionmentioning

confidence: 99%

Mechanically Robust and Self-Healing Elastomers Based on Dynamic Oxime–Carbamate Bonds: A Combined Experiment and All-Atom Simulation Study

Chen

et al. 2023

ACS Appl. Polym. Mater.

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Elastomers inevitably suffer scratches and damage during the application; thus, the design and fabrication of self-healing elastomers with covalent adaptive networks is a meaningful strategy to extend the service life of materials. In this study, a facile two-step approach was proposed to synthesize self-healing elastomers based on the dynamic oxime–carbamate bonds. Hydroxyl-terminated polybutadiene was first reacted with isophorone diisocyanate to synthesize the prepolymer with isocyanate groups terminated, followed by further reaction with dimethylglyoxime as a chain extender to obtain self-healing elastomers. Specially, all-atom molecular dynamics simulations were used to construct the same model as the experiments. Together with the experimental characterization of FTIR and 1H NMR, all-atom molecular dynamics simulations can further verify the formation of hydrogen bonds and dynamic oxime–carbamate bonds. By fixing the ratio of hydroxyl to isocyanate constant, we found that the mechanical strength increased with the increase of hard segment content. At the same time, the loss factor decreased in the glass transition region and at room temperature. Finally, the self-healing behavior of the elastomer was verified at a certain temperature. The corresponding mechanism is explained by means of molecular dynamics simulations, where dynamic oxime–carbamate bonds play more important roles than hydrogen bonds. The combined simulation and experimental studies provided a reasonable approach for the subsequent self-healing system.

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Manipulating the mechanical properties of cis-polyisoprene nanocomposites via molecular dynamics simulation

Cited by 18 publications

References 45 publications

Insights into Uniaxial Tension and Relaxation of Nanorod-Filled Polymer Vitrimer Nanocomposites: A Molecular Dynamics Simulation

Insights into Uniaxial Tension and Relaxation of Nanorod-Filled Polymer Vitrimer Nanocomposites: A Molecular Dynamics Simulation

Molecular dynamics simulation of the impact of the surface topology of carbon black on the mechanical properties of elastomer nanocomposites

Mechanically Robust and Self-Healing Elastomers Based on Dynamic Oxime–Carbamate Bonds: A Combined Experiment and All-Atom Simulation Study

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