Study on the crystallization behaviour of polyethylene grafted onto carbon nanotubes using molecular dynamics simulation

Han, Zixuan; Dong, Yanying; Tan, Zhi-Jie; Ma, Jiaqi; Yu, Ping

doi:10.1080/08927022.2020.1834101

Cited by 3 publications

(5 citation statements)

References 51 publications

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“…The gradual decrease in the non-bonding energy indicates re-arrangement of the chains from an amorphous state to a partially ordered state that pulls down the energy level over time. Similar observations were made in the previous studies that perform simulations on polyethylene and alkane. , The change in the orientational characteristics during this period is also verified in Figure c, where the mean value of the angle between PEEK chains’ backbone directions with respect to CNT is presented (Figure d). It is noted that all the simulations are performed close to the crystallization temperature which comes with advantages and disadvantages in terms of overcoming energy barriers to get different conformations.…”

Section: Resultssupporting

confidence: 87%

Fundamentals of Crystalline Evolution and Properties of Carbon Nanotube-Reinforced Polyether Ether Ketone Nanocomposites in Fused Filament Fabrication

Carrola

Fallahi

Koerner

et al. 2023

ACS Appl. Mater. Interfaces

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As fused filament fabrication (FFF) continues to gain popularity, many studies are turning to nanomaterials or optimization of printing parameters to improve the materials’ properties; however, many overlook how materials formulation and additive manufacturing (AM) processes cooperatively engineer the evolution of properties across length scales. Evaluating the in-process evolution of the nanocomposite using AM will provide a fundamental understanding of the material’s microstructure, which can be tailored to create unique characteristics in functionality and performance. In this study, the crystallinity behavior of polyetheretherketone (PEEK) was studied in the presence of carbon nanotubes (CNTs) as a nucleation aid for improved crystallization during FFF processing. Using various characterization techniques and molecular dynamics simulations, it was discovered that the crystallization behavior of extruded filaments is very different from that of 3D printed roads. Additionally, the printed material exhibited cold crystallization, and the CNT addition increased the crystallization of printed roads, which were amorphous without CNT addition. Tensile strength and modulus were increased by as much as 42 and 51%, respectively, due to higher crystallinity during printing. Detailed knowledge on the morphology of PEEK–CNT used in FFF allows gaining a fundamental understanding of the morphological evolution occurring during the AM process that in turn enables formulating materials for the AM process to achieve tailored mechanical and functional properties, such as crystallinity or conductivity.

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Section: Resultssupporting

confidence: 87%

Fundamentals of Crystalline Evolution and Properties of Carbon Nanotube-Reinforced Polyether Ether Ketone Nanocomposites in Fused Filament Fabrication

Carrola

Fallahi

Koerner

et al. 2023

ACS Appl. Mater. Interfaces

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“…Previous efforts have used MD simulations to understand the influence of nanoconfinement on the thermomechanical properties of amorphous polymer systems [ 39 , 40 , 41 ]. Additionally, MD simulations have been previously applied to study polymer crystallization [ 42 , 43 , 44 , 45 , 46 ]. However, only a small number have investigated the crystallization of polymers under nanoconfinement.…”

Section: Introductionmentioning

confidence: 99%

“…Jabbarzadeh investigated the effect of gold nanoparticles on the crystallization of polymers using large-scale MD simulations, and the results showed that the nanoparticles decreased the overall degree of crystallinity [ 45 ]. Han and co-workers studied the crystallization of polyethylene grafted onto carbon nanotubes by using MD simulation, and the results showed that the final crystallinity of the polymer increased with larger grafting density [ 46 ]. These two atomistic MD studies were limited in the spatiotemporal scale they could reach.…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Nanoconfinement Effect on Crystallization of Semicrystalline Polymers Using Coarse-Grained Molecular Dynamics Simulations

Yang,

Chen,

Yang

et al. 2024

Polymers

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Semicrystalline polymers under nanoconfinement show distinct structural and thermomechanical properties compared to their bulk counterparts. Despite extensive research on semicrystalline polymers under nanoconfinement, the nanoconfinement effect on the local crystallization process and the unique structural evolution of such polymers have not been fully understood. In this study, we unveil such effects by using coarse-grained molecular dynamics simulations to study the crystallization process of a model semicrystalline polymer—polyvinyl alcohol (PVA)—under different levels of nanoconfinement induced by nanoparticles that are represented implicitly. We quantify in detail the evolution of the degree of crystallinity (XC) of PVA and examine distinct crystalline regions from simulation results. The results show that nanoconfinement can promote the crystallization process, especially at the early stage, and the interfaces between nanoparticles and polymer can function as crystallite nucleation sites. In general, the final XC of PVA increases with the levels of nanoconfinement. Further, nanoconfined cases show region-dependent XC with higher and earlier increase of XC in regions closer to the interfaces. By tracking region-dependent XC evolution, our results indicate that nanoconfinement can lead to a heterogenous crystallization process with a second-stage crystallite nucleation in regions further away from the interfaces. In addition, our results show that even under very high cooling rates, the nanoconfinement still promotes the crystallization of PVA. This study provides important insights into the underlying mechanisms for the intricate interplay between nanoconfinement and the crystallization behaviors of semicrystalline polymer, with the potential to guide the design and characterization of semicrystalline polymer-based nanocomposites.

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“…40,41 Han et al focused on the crystallization of hexadecane grafted on the surface of carbon nanotube with all-atom MD and reported that the crystallinity becomes higher with the grafting density. 42 Lattice models were also implemented with Monte Carlo simulations for polymers grafted on fillers. 43−46 The computed dependences of the crystallization temperature on the grafting density and the molecular weight were in qualitative agreement with experimental observations, and the role of the crowding effect was pointed out.…”

Section: Introductionmentioning

confidence: 99%

“…Molecular dynamics (MD) simulation is a method of choice for investigating crystallization processes of polymers at the molecular scale. There were several studies of homogeneous nucleation of polymer chains in the 1990s, although the length of polymer chains and the number of trajectories were limited due to the computational resources available at the time. − Simulations of long polymer chains were performed in more recent studies. − The critical nuclear size and the free energy for nucleation were calculated by Yi et al ,, Crystallization of polymers in the presence of interfaces , or shear flow were also investigated using MD simulations. , Han et al focused on the crystallization of hexadecane grafted on the surface of carbon nanotube with all-atom MD and reported that the crystallinity becomes higher with the grafting density . Lattice models were also implemented with Monte Carlo simulations for polymers grafted on fillers. − The computed dependences of the crystallization temperature on the grafting density and the molecular weight were in qualitative agreement with experimental observations, and the role of the crowding effect was pointed out.…”

Section: Introductionmentioning

confidence: 99%

Crystallization of Polyethylene Brushes and Its Effect on Interactions with Water

Yagasaki

Matubayasi

2021

Macromolecules

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The crystallization process of brushes of polyethylene chains is investigated using all-atom molecular dynamics simulations at degrees of polymerization of 40 and 120. Through temperature reduction in nanosecond time scales, spontaneous crystallization is observed for polymer chains that are grafted on gold crystals and are in contact with vacuum on the other side. Crystalline nuclei form in the middle region of the brushes separated by nanometers from the gold and vacuum interfaces. The crystallization actually begins when the density of carbon atoms exceeds a threshold value. Increases in the grafting density and/or the degree of polymerization result in an increase in the density of carbon atoms in the middle region of the brush and thus leads to an elevation in the crystallization temperature. The free energy of inserting a water molecule into the brush is also analyzed. It is found to be more unfavorable in the crystalline brush than in the fluid state. This is due to the high density of the crystalline state, and in locally disordered regions in the crystalline brush, the insertion free energy is comparable to that in the fluid.

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Study on the crystallization behaviour of polyethylene grafted onto carbon nanotubes using molecular dynamics simulation

Cited by 3 publications

References 51 publications

Fundamentals of Crystalline Evolution and Properties of Carbon Nanotube-Reinforced Polyether Ether Ketone Nanocomposites in Fused Filament Fabrication

Fundamentals of Crystalline Evolution and Properties of Carbon Nanotube-Reinforced Polyether Ether Ketone Nanocomposites in Fused Filament Fabrication

Unveiling the Nanoconfinement Effect on Crystallization of Semicrystalline Polymers Using Coarse-Grained Molecular Dynamics Simulations

Crystallization of Polyethylene Brushes and Its Effect on Interactions with Water

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