• Issue
    Volume 31, Issue 1
    January 2022

Cover Picture

Free Access

Coarse-Grained Molecular Simulation of Polymers Supported by the Use of the SAFT-γ Mie Equation of State

  • First Published: 19 January 2022
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Front Cover: Snapshot of the liquid-liquid interface of polypropylene 50.4 kDa (green) in n-pentane (gray) at 470 K and 40 MPa at 25 w% global composition modelled using a coarse-grained SAFT-γ Mie force field. Parameters for the intermolecular potential are derived in a top-down approach using the equation of state and experimental pure component data. This is reported by Maziar Fayaz-Torshizi and Erich A. Müller in article number 2100031.

Masthead

Free Access

Masthead: Macromol. Theory Simul. 1/2022

  • First Published: 19 January 2022

Research Articles

Open Access

Coarse-Grained Molecular Simulation of Polymers Supported by the Use of the SAFT- γ $\gamma$ Mie Equation of State

  • First Published: 23 September 2021
Description unavailable

A coarse-grained force field which allows the molecular simulation of polymers, their blends, and mixtures with solvents is presented. The parametrization of the intermolecular potentials is done with the aid of an equation of state, which allows for robust and transferrable parameters. Examples are provided of different types of liquid–liquid equilibria for a selected group of case studies.

Open Access

Three-Dimensional Finite Element Modeling of a Viscous Fluid Flowing through an External Gear Pump

  • First Published: 22 October 2021
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In extrusion processes, external gear pumps are frequently used to transport all kinds of fluids. 3D simulations are performed using the finite element method to investigate the relative importance of the radial and axial clearances in the pump. Particle tracking reveals zones with infinite residence time.

Free to Read

Simulation of Polymer Melt Injection Molding Filling Flow Based on an Improved SPH Method with Modified Low-Dissipation Riemann Solver

  • First Published: 18 August 2021
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Simulations of polymer melt injection molding filling flow are performed using an improved smoothed particle hydrodynamics (SPH) method. A new combination of several techniques is adopted, including an originally proposed low-dissipation Riemann solver, the Tait equation of state, and several other improvements. SPH simulations with three cavities are performed for verification and compared with the Moldflow results with good agreement.

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Toward a Better Understanding of Activation Volume and Dynamic Decoupling of Glass-Forming Liquids under Compression

  • First Published: 08 August 2021
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Elastically collective nonlinear Langevin equation theory is used to calculate the temperature and pressure dependence of structural relaxation time of ternidazole, glycerol, and probucol. The power law decoupling of pressure changed mobility compared to relaxation in ambient condition is found. The decoupling exponent is found to exponentially vary with pressure.

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Physical Origin of Distinct Mechanical Properties of Polymer Tethered Graphene Nanosheets Reinforced Polymer Nanocomposites Revealed by Nonequilibrium Molecular Dynamics Simulations

  • First Published: 19 August 2021
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The physical principles of distinct mechanical properties of the polymer nanocomposites reinforced by polymer tethered graphene nanosheets are revealed by the nonequilibrium molecular dynamics simulations. The stronger interfacial interactions will induce the closer packing distance with smaller free volume, higher polymer chain entanglement, and higher restriction of polymer chain movement, which synergistically contribute to the improvement in the mechanical properties.

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Effect of Initiator Structure on Thiol-Ene Polymerization: A DFT Study

  • First Published: 01 September 2021
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Thiyl radicals formed from the reaction of initiator radicals with thiols can be eager to follow the thiol-ene procedure. However, there is a possibility of homopolymerization initiation as a side reaction that consumes ene functionality and results in a heterogeneity increase of thiol-ene polymer product. Therefore, initiator preference plays a significant role in thiol-ene polymerization.

Open Access

Simple Model for the Spreading of Inks in Bioprinting—Revealing Relevant Scaling Laws—Part I Theory

  • First Published: 15 September 2021
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A model taking into consideration viscosity and evaporation is suggested to describe the 1D spreading kinetics of struts in bioprinting. Applicable fit functions and predictive scaling laws are given, relating viscosity of bioinks, process parameters such as print speed and throughput to the strut width. The approach is primarily based on 1D spreading, indicated by the figure.

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Theory of Y- and Comb-Shaped Polymer Brushes: The Parabolic Potential Framework

  • First Published: 12 September 2021
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The applicability of the parabolic approximation for self-consistent molecular potential in brushes of Y- and comb-shaped polymers is verified by numerical self-consistent field Scheutjens–Fleer method. Violation of the parabolic shape of the potential is evidenced for comb-like polymers with small number of repeats and for the macromolecules with relatively short root spacers and is manifested in appearance of dead zone and multimodal distribution of the end segment in the longest elastic path.

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Model Simulation of Creep and Thermal Ratcheting of Engineering Polymers

  • First Published: 08 September 2021
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A viscoelastic model's capability of describing thermal fluctuations of polymers utilized as components of pressure vessel and piping is presented. By simulating a simple creep curve at a specific temperature, the model parameters could be evaluated. Hereafter, by imposing a thermal cycling process, two additional parameters could be acquired. The thermal ratcheting could be captured with a good accuracy.