Thermal Conductivity of Polybutadiene Rubber from Molecular Dynamics Simulations and Measurements by the Heat Flow Meter Method

Васильев, А. Н.; Lorenz, Tommy; Kamble, Vikram G.; Wießner, Sven; Breitkopf, Cornelia

doi:10.3390/ma14247737

Cited by 9 publications

(9 citation statements)

References 33 publications

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“…One approach to validating the potential function is to compare the results of the MD simulation with experimental data. In [54], the same potential functions and parameters were utilized, and the results of the simulations were appropriately in line with the experiments, which indicates that the relevant potential functions and parameters have been considered appropriately. Table 1 provides an overview of the Lennard-Jones potential parameters as well as other force fields used in the MD simulations.…”

Section: Representation Of Cis-14-polybutadiene In MD Simulationsmentioning

confidence: 62%

“…Nevertheless, excessive amounts of sulfur can result in over-crosslinking, which may cause the material to become brittle and lose its elasticity [59]. For producing PB crosslinked with sulfur in [54], the amount of sulfur has been considered to be 2.8 phr (parts per hundred of rubber), according to the desired purpose.…”

Section: Polybutadiene Crosslinked With Randomly Distributed Sulfur O...mentioning

confidence: 99%

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Glass Transition Temperatures and Thermal Conductivities of Polybutadiene Crosslinked with Randomly Distributed Sulfur Chains Using Molecular Dynamic Simulation

Alamfard,

Lorenz,

Breitkopf

2024

Polymers

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The thermal conductivities and glass transition temperatures of polybutadiene crosslinked with randomly distributed sulfur chains having different lengths from mono-sulfur (S1) to octa-sulfur (S8) were investigated. The thermal conductivities of the related models as a function of the heat flux autocorrelation function, applying an equilibrium molecular dynamic (EMD) simulation and the Green–Kubo method, were studied for a wide range of temperatures. The influence of the length of sulfur chains, degree of crosslinking, and molar mass of the crosslinker on the glass transition temperature and final values of thermal conductivities were studied. First, the degree of crosslinking is considered constant for the eight simulation models, from mono-sulfur (S1) to octa-sulfur (S8), while the molar mass of the sulfur is increases. The results show that the thermal conductivities of the crosslinked structure decrease with increasing temperature for each model. Moreover, by increasing the lengths of the sulfur chains and the molar weight of the crosslinker, thermal conductivity increases at a constant temperature. The MD simulation demonstrates that the glass transition temperature and density of the crosslinked structure enhance as the length of the sulfur chains and molar mass of the sulfur increase. Second, the molar weight of sulfur is considered constant in these eight models; therefore, the degree of crosslinking decreases with the increase in the lengths of the sulfur chains. The results show that the thermal conductivities of the crosslinked structure decrease with the increase in the temperature for each model. Moreover, by increasing the lengths of sulfur chains and thus decreasing the degree of crosslinking, the trend in changes in thermal conductivities are almost the same for all of these models, so thermal conductivity is constant for a specific temperature. In addition, the glass transition temperature and density of the crosslinked structure decrease.

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Section: Representation Of Cis-14-polybutadiene In MD Simulationsmentioning

confidence: 62%

Section: Polybutadiene Crosslinked With Randomly Distributed Sulfur O...mentioning

confidence: 99%

Glass Transition Temperatures and Thermal Conductivities of Polybutadiene Crosslinked with Randomly Distributed Sulfur Chains Using Molecular Dynamic Simulation

Alamfard,

Lorenz,

Breitkopf

2024

Polymers

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“…This method can be used to measure the TC of glass, ceramics, polymers, and insulation materials [ 101 , 194 ]. The TC of the material can then be calculated using the following equation [ 195 ]:

where L is the thickness of the specimen, and Δ T is the temperature difference between the upper and lower surfaces of the specimen.…”

Section: Tc Measurement Techniques and Computational Simulationsmentioning

confidence: 99%

Thermal Conductivity Enhancement of Polymeric Composites Using Hexagonal Boron Nitride: Design Strategies and Challenges

Meng,

Yang,

Jiang

et al. 2024

Nanomaterials

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With the integration and miniaturization of chips, there is an increasing demand for improved heat dissipation. However, the low thermal conductivity (TC) of polymers, which are commonly used in chip packaging, has seriously limited the development of chips. To address this limitation, researchers have recently shown considerable interest in incorporating high-TC fillers into polymers to fabricate thermally conductive composites. Hexagonal boron nitride (h-BN) has emerged as a promising filler candidate due to its high-TC and excellent electrical insulation. This review comprehensively outlines the design strategies for using h-BN as a high-TC filler and covers intrinsic TC and morphology effects, functionalization methods, and the construction of three-dimensional (3D) thermal conduction networks. Additionally, it introduces some experimental TC measurement techniques of composites and theoretical computational simulations for composite design. Finally, the review summarizes some effective strategies and possible challenges for the design of h-BN fillers. This review provides researchers in the field of thermally conductive polymeric composites with a comprehensive understanding of thermal conduction and constructive guidance on h-BN design.

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“…NEMD methods are based on obtaining a constant temperature gradient and the heat flux inside a modeled system and the application of the Fourier’s heat transfer equation, when the type of heat transfer is diffusive. In these simulations, the system is divided into slabs, and two of them are defined as hot and cold slabs, which serve as hot and cold plates in a real experiment (for example, the guarded hot plate and heat flow meter methods [ 10 ]). There are three algorithms in NEMD simulations that can be used to obtain the steady state regime inside the system.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the composition of TPU, which consists of hard and soft segments (see Simulation Details), different thermo-mechanical properties of TPU can be achieved by adjusting the proportion of the segments. For a first evaluation, those tendencies can be investigated by MD simulations, which was done in this research, based on the optimized force field used [ 10 , 34 ]. The results of thermal conductivities are important for the modeling of fibers based on TPU by FEM [ 35 , 36 ].…”

Section: Introductionmentioning

confidence: 99%

Prediction of Thermal Conductivities of Rubbers by MD Simulations—New Insights

2022

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In this article, two main approaches to the prediction of thermal conductivities by molecular dynamics (MD) simulations are discussed, namely non-equilibrium molecular dynamics simulations (NEMD) and the application of the Green–Kubo formula, i.e., EMD. NEMD methods are more affected by size effects than EMD methods. The thermal conductivities of silicone rubbers in special were found as a function of the degree of crosslinking. Moreover, the thermal conductivities of thermoplastic polyurethane as function of the mass fraction of soft segments were obtained by those MD simulations. All results are in good agreement with data from the experimental literature. After the analysis of normalized heat flux autocorrelation functions, it has been revealed that heat in the polymers is mainly transferred by low-frequency phonons. Simulation details as well as advantages and disadvantages of the single methods are discussed in the article.

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Thermal Conductivity of Polybutadiene Rubber from Molecular Dynamics Simulations and Measurements by the Heat Flow Meter Method

Cited by 9 publications

References 33 publications

Glass Transition Temperatures and Thermal Conductivities of Polybutadiene Crosslinked with Randomly Distributed Sulfur Chains Using Molecular Dynamic Simulation

Glass Transition Temperatures and Thermal Conductivities of Polybutadiene Crosslinked with Randomly Distributed Sulfur Chains Using Molecular Dynamic Simulation

Thermal Conductivity Enhancement of Polymeric Composites Using Hexagonal Boron Nitride: Design Strategies and Challenges

Prediction of Thermal Conductivities of Rubbers by MD Simulations—New Insights

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