1
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Jawed A, Khan MN, Khan NA, Hakeem MA, Khan P. Thermodynamic Insights into Variation in Thermomechanical and Physical Properties of Isotactic Polypropylene: Effect of Shear and Cooling Rates. ACS OMEGA 2023; 8:36775-36788. [PMID: 37841128 PMCID: PMC10569009 DOI: 10.1021/acsomega.3c03378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/24/2023] [Indexed: 10/17/2023]
Abstract
In order to elucidate the effect of shear and cooling process on structural, thermomechanical, and physical properties of polymer melt, excess entropy, a thermodynamic quantity is calculated from radial distribution function generated from equilibrated parts of the molecular simulation trajectories. The structural properties are calculated, which includes the density of polypropylene melt, end to end distance, radius of gyration of the polypropylene polymer chain, and monomer-monomer radial distribution function. Non-equilibrium molecular dynamics simulation was employed to investigate the role of the applied shear rate on the properties of polypropylene. Furthermore, a range of cooling rates were employed to cool the melt. Thermomechanical properties, such as Young's modulus, and physical properties, such as glass transition temperature, were determined for different cases. Results showed that slow cooling and high shear substantially improved the Young's modulus and glass transition temperature of the i-PP. Furthermore, a two-body contribution to the excess entropy was used to elucidate the structure-property relationships in the polymer melt as well as the glassy state and the dependence of shear and cooling rate on these properties. We have used the Rosenfeld excess entropy-viscosity relationship to calculate the viscous behavior of the polymer under a steady shear condition.
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Affiliation(s)
- Ahmad
S. Jawed
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh 202002, India
| | - Mohd Nasir Khan
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh 202002, India
| | - Naseem A. Khan
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh 202002, India
| | - Mohammed A. Hakeem
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh 202002, India
| | - Parvez Khan
- Department of Chemical Engineering, Aligarh Muslim University, Aligarh 202002, India
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2
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Sigalas NI, Anogiannakis SD, Theodorou DN, Lyulin AV. A coarse-grained model for capturing the helical behavior of isotactic polypropylene. SOFT MATTER 2022; 18:3076-3086. [PMID: 35373807 DOI: 10.1039/d2sm00200k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Understanding the process-property relations of helical polymers using molecular simulations has been an attractive research field over the years. Specifically, isotactic polypropylene still remains a challenge for current computational experimentation, as it exhibits phenomena such as crystallization that emerge on large spatial and temporal scales. Coarse-graining is an efficient technique for approaching such phenomena, although previous coarse-grained models lack in preserving important atomistic and structural details. In this paper we develop a new coarse-grained model, based on the popular MARTINI force field, that is able to reproduce the helical behavior of isotactic polypropylene. To test the model, the predicted statistical and structural properties (characteristic ratio, density, entanglement molecular weight, solubility parameter in the melt) are compared with previous simulation results and available experimental data. For the development of the new coarse-grained force field, a single unperturbed chain Monte Carlo algorithm has been implemented: an efficient algorithm which samples conformations representative of a melt by simulating just a single chain.
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Affiliation(s)
- Nikolaos I Sigalas
- Soft Matter and Biological Physics Group, Department of Applied Physics, Technische Universiteit Eindhoven, 5600, MB, Eindhoven, The Netherlands.
- Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
| | - Stefanos D Anogiannakis
- Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
- Computational Materials Science and Engineering Group, School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Doros N Theodorou
- Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands
- Computational Materials Science and Engineering Group, School of Chemical Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece
| | - Alexey V Lyulin
- Soft Matter and Biological Physics Group, Department of Applied Physics, Technische Universiteit Eindhoven, 5600, MB, Eindhoven, The Netherlands.
- Center for Computational Energy Research (CCER), P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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3
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Sattor AK, Pervaje AK, Pasquinelli MA, Khan SA, Santiso EE. Multiscale Constitutive Modeling of the Mechanical Properties of Polypropylene Fibers from Molecular Simulation Data. Macromolecules 2022. [DOI: 10.1021/acs.macromol.1c00630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Amulya K. Sattor
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Amulya K. Pervaje
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Melissa A. Pasquinelli
- Fiber and Polymer Science Program, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Saad A. Khan
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Erik E. Santiso
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
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4
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Fayaz‐Torshizi M, Müller EA. Coarse‐Grained Molecular Simulation of Polymers Supported by the Use of the SAFT‐γ$\gamma$ Mie Equation of State. MACROMOL THEOR SIMUL 2021. [DOI: 10.1002/mats.202100031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Erich A. Müller
- Department of Chemical Engineering Imperial College London London SW7 2AZ UK
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5
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Wang A, Vargas-Lara F, Younker JM, Iyer KA, Shull KR, Keten S. Quantifying Chemical Composition and Cross-link Effects on EPDM Elastomer Viscoelasticity with Molecular Dynamics. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Jarod M. Younker
- ExxonMobil Chemical Company, Baytown, Texas 77520, United States
| | - Krishnan A. Iyer
- ExxonMobil Chemical Company, Baytown, Texas 77520, United States
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6
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Vuković F, Swan SR, Reyes LQ, Varley RJ, Walsh TR. Beyond the ring flip: A molecular signature of the glass–rubber transition in tetrafunctional epoxy resins. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122893] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Singh SK, Kunche L, Natarajan U. Detailed Molecular Structure of Glassy Poly(phenylene oxide) (PPO) Studied by Molecular Dynamics Simulations. J MACROMOL SCI B 2020. [DOI: 10.1080/00222348.2020.1806579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Sanjeet Kumar Singh
- Macromolecular Modeling and Materials Simulation Laboratory, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
| | - Lakshmikumar Kunche
- Macromolecular Modeling and Materials Simulation Laboratory, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
| | - Upendra Natarajan
- Macromolecular Modeling and Materials Simulation Laboratory, Department of Chemical Engineering, Indian Institute of Technology (IIT) Madras, Chennai, India
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8
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Ricci E, Vergadou N, Vogiatzis GG, De Angelis MG, Theodorou DN. Molecular Simulations and Mechanistic Analysis of the Effect of CO 2 Sorption on Thermodynamics, Structure, and Local Dynamics of Molten Atactic Polystyrene. Macromolecules 2020; 53:3669-3689. [PMID: 33828339 PMCID: PMC8016389 DOI: 10.1021/acs.macromol.0c00323] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 04/21/2020] [Indexed: 11/30/2022]
Abstract
A simulation strategy encompassing different scales was applied to the systematic study of the effects of CO2 uptake on the properties of atactic polystyrene (aPS) melts. The analysis accounted for the influence of temperature between 450 and 550 K, polymer molecular weights (M w) between 2100 and 31000 g/mol, and CO2 pressures up to 20 MPa on the volumetric, swelling, structural, and dynamic properties of the polymer as well as on the CO2 solubility and diffusivity by performing molecular dynamics (MD) simulations of the system in a fully atomistic representation. A hierarchical scheme was used for the generation of the higher M w polymer systems, which consisted of equilibration at a coarse-grained level of representation through efficient connectivity-altering Monte Carlo simulations, and reverse-mapping back to the atomistic representation, obtaining the configurations used for subsequent MD simulations. Sorption isotherms and associated swelling effects were determined by using an iterative procedure that incorporated a series of MD simulations in the NPT ensemble and the Widom test particle insertion method, while CO2 diffusion coefficients were extracted from long MD runs in the NVE ensemble. Solubility and diffusivity compared favorably with experimental results and with predictions of the Sanchez-Lacombe equation of state, which was reparametrized to capture the M w dependence of polymer properties with greater accuracy. Structural features of the polymer matrix were correctly reproduced by the simulations, and the effects of gas concentration and M w on structure and local dynamics were thoroughly investigated. In the presence of CO2, a significant acceleration of the segmental dynamics of the polymer occurred, more pronouncedly at low M w. The speed-up effect caused by the swelling agent was not limited to the chain ends but affected the whole chain in a similar fashion.
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Affiliation(s)
- Eleonora Ricci
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Bologna, Italy
| | - Niki Vergadou
- Institute of Nanoscience and Nanotechnology, National Center for Scientific Research "Demokritos", Athens, Greece
| | - Georgios G Vogiatzis
- Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Maria Grazia De Angelis
- Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, Bologna, Italy
| | - Doros N Theodorou
- School of Chemical Engineering, National Technical University of Athens, Athens, Greece
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9
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Rondina GG, Böhm MC, Müller-Plathe F. Predicting the Mobility Increase of Coarse-Grained Polymer Models from Excess Entropy Differences. J Chem Theory Comput 2020; 16:1431-1447. [DOI: 10.1021/acs.jctc.9b01088] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gustavo G. Rondina
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany
| | - Michael C. Böhm
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany
| | - Florian Müller-Plathe
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 8, 64287 Darmstadt, Germany
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10
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Kallivokas SV, Sgouros AP, Theodorou DN. Molecular dynamics simulations of EPON-862/DETDA epoxy networks: structure, topology, elastic constants, and local dynamics. SOFT MATTER 2019; 15:721-733. [PMID: 30629083 DOI: 10.1039/c8sm02071j] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Structural, topological, mechanical and dynamical properties of EPON-862/DETDA epoxy networks are investigated with Molecular Dynamics (MD) simulations. The epoxy networks are composed of the resin Diglycidyl Ether Bisphenol F (DGEBF), also known as EPON-862, and the hardener Diethyl Toluene Diamine (DETDA). Systems with four different crosslinking degrees are examined; the effect of the degree of crosslinking on studied properties is thus determined. The computed quantities are retrieved by employing several simulation strategies and numerical methods of statistical mechanics in order to gain a rigorous and solid understanding of the aforementioned properties as well as to assess the accuracy and applicability of the methods employed. We quantify and analyze the local structure of the EPON-862/DETDA epoxy networks through the partial pair distribution functions, the Faber-Ziman partial structure factors and through simulated X-ray diffraction patterns, demonstrating good agreement with an experimental spectrum from a similar epoxy resin. The topology of the networks is examined with the aim of assessing percolation of connectivity, the properties of network fragments (subnetworks), and the distribution of functionalities of the crosslinks. The elastic constants of the systems are retrieved by employing two equilibrium (analysis of volume fluctuations, Parrinello-Rahman strain fluctuation relation) and one nonequilibrium (uniaxial tension/compression deformations at prescribed rate) method. Finally, the glass temperatures of the systems are estimated by calculating the density as a function of temperature and by analyzing the reorientational dynamics of bond vectors which describe relaxation processes at the segment level.
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Affiliation(s)
- Spyros V Kallivokas
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Aristotelis P Sgouros
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
| | - Doros N Theodorou
- School of Chemical Engineering, Department of Materials Science and Engineering, National Technical University of Athens (NTUA), GR-15780 Athens, Greece.
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11
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Tzounis PN, Argyropoulou DV, Anogiannakis SD, Theodorou DN. Tacticity Effect on the Conformational Properties of Polypropylene and Poly(ethylene–propylene) Copolymers. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01099] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
| | - Dora V. Argyropoulou
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
| | - Stefanos D. Anogiannakis
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
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12
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F Behbahani A, Vaez Allaei SM, H Motlagh G, Eslami H, Harmandaris VA. Structure and dynamics of stereo-regular poly(methyl-methacrylate) melts through atomistic molecular dynamics simulations. SOFT MATTER 2018; 14:1449-1464. [PMID: 29393331 DOI: 10.1039/c7sm02008b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Poly(methyl-methacrylate), PMMA, is a disubstituted vinyl polymer whose properties depend significantly on its tacticity. Here we present a detailed study of the structure, conformation, and dynamics of syndiotactic, atactic, and isotactic PMMA melts at various temperatures (580, 550, 520, and 490 K) via all-atom molecular dynamics simulations. The calculated volumetric properties are close to experimental data. The Tg and chain dimensions of PMMA model systems are found to depend strongly on tacticity in agreement with experimental findings. The backbone bonds in trans (t), diads in tt, and inter-diads in t|t torsional states are the most populated for all PMMA stereo-chemistries and their fractions increase with the number of syndiotactic sequences. Also, the effective torsional barrier heights for the backbone, ester side group, and α-methyl group are larger for syndiotactic PMMA compared to the isotactic one. The structure of the PMMA chains is studied by computing the intra- and inter-chain static structure factors, S(q), and the radial pair distribution functions. In the first peak of S(q), both intra- and inter-chain components contribute, whereas the second and third peaks mainly come from inter- and intra-chain parts, respectively. For all PMMA stereo-isomers a clear tendency of ester-methyl groups to aggregate is observed. The local dynamics are studied by analyzing torsional autocorrelation functions for various dihedral angles. A wide spectrum of correlation times and different activation energies are observed for the motions of different parts of PMMA chains. The stereo-chemistry affects the backbone, ester side group, and α-methyl motions, whereas the ester-methyl rotation remains unaffected. The dynamic heterogeneity of the PMMA chains is also studied in detail for the different stereo-chemistries via the temperature dependence of the stretching exponent. Furthermore, the reorientational dynamics at the chain level and translational dynamics for monomer and chain centers-of-mass are analyzed.
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Affiliation(s)
- Alireza F Behbahani
- Advanced Polymer Materials and Processing Lab, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran 11155-4563, Iran
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13
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Tzounis PN, Anogiannakis SD, Theodorou DN. General Methodology for Estimating the Stiffness of Polymer Chains from Their Chemical Constitution: A Single Unperturbed Chain Monte Carlo Algorithm. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b00645] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Stefanos D. Anogiannakis
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, GR 15780 Athens, Greece
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14
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Vogiatzis GG, Theodorou DN. Multiscale Molecular Simulations of Polymer-Matrix Nanocomposites: or What Molecular Simulations Have Taught us About the Fascinating Nanoworld. ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING : STATE OF THE ART REVIEWS 2017; 25:591-645. [PMID: 29962833 PMCID: PMC6003436 DOI: 10.1007/s11831-016-9207-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/20/2016] [Indexed: 06/08/2023]
Abstract
Following the substantial progress in molecular simulations of polymer-matrix nanocomposites, now is the time to reconsider this topic from a critical point of view. A comprehensive survey is reported herein providing an overview of classical molecular simulations, reviewing their major achievements in modeling polymer matrix nanocomposites, and identifying several open challenges. Molecular simulations at multiple length and time scales, working hand-in-hand with sensitive experiments, have enhanced our understanding of how nanofillers alter the structure, dynamics, thermodynamics, rheology and mechanical properties of the surrounding polymer matrices.
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Affiliation(s)
- Georgios G. Vogiatzis
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
- Present Address: Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven, The Netherlands
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, 15780 Athens, Greece
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15
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Wu C. Glass transition in single poly(ethylene oxide) chain: A molecular dynamics simulation study. ACTA ACUST UNITED AC 2016. [DOI: 10.1002/polb.24255] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Chaofu Wu
- College of Materials and Environment Engineering; Hunan University of Humanities Science and Technology; Dixing Road 487, Louxing District Loudi Hunan Province 417000 The People's Republic of China
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16
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Mathioudakis IG, Vogiatzis GG, Tzoumanekas C, Theodorou DN. Multiscale simulations of PS-SiO2 nanocomposites: from melt to glassy state. SOFT MATTER 2016; 12:7585-7605. [PMID: 27532769 DOI: 10.1039/c6sm01536k] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The interaction energetics, molecular packing, entanglement network properties, segmental dynamics, and elastic constants of atactic polystyrene-amorphous silica nanocomposites in the molten and the glassy state are studied via molecular simulations using two interconnected levels of representation: (a) a coarse-grained one, wherein each polystyrene repeat unit is mapped onto a single "superatom" and the silica nanoparticle is viewed as a solid sphere. Equilibration at all length scales at this level is achieved via connectivity-altering Monte Carlo simulations. (b) A united-atom (UA) level, wherein the polymer chains are represented in terms of a united-atom forcefield and the silica nanoparticle is represented in terms of a simplified, fully atomistic model. Initial configurations for UA molecular dynamics (MD) simulations are obtained by reverse mapping well-equilibrated coarse-grained configurations. By analysing microcanonical UA MD trajectories, the polymer density profile is studied and the polymer is found to exhibit layering in the vicinity of the nanoparticle surface. An estimate of the enthalpy of mixing between polymer and nanoparticles, derived from the UA simulations, compares favourably against available experimental values. The dynamical behaviour of polystyrene (in neat and filled melt systems) is characterized in terms of bond orientation and dihedral angle time autocorrelation functions. At low concentration in the molten polymer matrix, silica nanoparticles are found to cause a slight deceleration of the segmental dynamics close to their surface compared to the bulk polymer. Well-equilibrated coarse-grained long-chain configurations are reduced to entanglement networks via topological analysis with the CReTA algorithm, yielding a slightly lower density of entanglements in the filled than in the neat systems. UA melt configurations are glassified by MD cooling. The elastic moduli of the resulting glassy nanocomposites are computed through an analysis of strain fluctuations in the undeformed state and through explicit mechanical deformation by MD, showing a stiffening of the polymer in the presence of nanoparticles. UA simulation results for the elastic constants are compared to continuum micromechanical calculations invoked in homogenization models of the overall mechanical behaviour of heterogeneous materials. They can be interpreted in terms of the presence of an "interphase" of approximate thickness 2 nm around the nanoparticles, with elastic constants intermediate between those of the filler and the matrix.
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Affiliation(s)
- I G Mathioudakis
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus, GR-15780 Athens, Greece.
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17
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Long L, Yang Y, Qiu F. All-Atom Molecular Dynamics Simulation of Structure and Diffusion of Hydrophilic Antistatic Agents in Polypropylene. CHINESE J CHEM 2014. [DOI: 10.1002/cjoc.201300843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Ji X, He X, Jiang S. Melting processes of oligomeric α and β isotactic polypropylene crystals at ultrafast heating rates. J Chem Phys 2014; 140:054901. [PMID: 24511973 DOI: 10.1063/1.4862901] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The melting behaviors of α (stable) and β (metastable) isotactic polypropylene (iPP) crystals at ultrafast heating rates are simulated with atomistic molecular dynamics method. Quantitative information about the melting processes of α- and β-iPP crystals at atomistic level is achieved. The result shows that the melting process starts from the interfaces of lamellar crystal through random dislocation of iPP chains along the perpendicular direction of lamellar crystal structure. In the melting process, the lamellar crystal gradually expands but the corresponding thickness decreases. The analysis shows that the system expansion lags behind the crystallinity decreasing and the lagging extents for α- and β-iPP are significantly different. The apparent melting points of α- and β-iPP crystals rise with the increase of the heating rate and lamellar crystal thickness. The apparent melting point of α-iPP crystal is always higher than that of β-iPP at differently heating rates. Applying the Gibbs-Thomson rule and the scaling property of the melting kinetics, the equilibrium melting points of perfect α- and β-iPP crystals are finally predicted and it shows a good agreement with experimental result.
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Affiliation(s)
- Xiaojing Ji
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Xuehao He
- Department of Chemistry, School of Science, Tianjin University, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Shichun Jiang
- School of Material, Tianjin University, Tianjin 300072, China
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19
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Vogiatzis GG, Theodorou DN. Local Segmental Dynamics and Stresses in Polystyrene–C60 Mixtures. Macromolecules 2013. [DOI: 10.1021/ma402214r] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Georgios G. Vogiatzis
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou
Campus, GR-15780 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou
Campus, GR-15780 Athens, Greece
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21
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Farago J, Meyer H, Baschnagel J, Semenov AN. Hydrodynamic and viscoelastic effects in polymer diffusion. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:284105. [PMID: 22738798 DOI: 10.1088/0953-8984/24/28/284105] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We develop a fluctuating hydrodynamics approach to study the impact of the hydrodynamic and viscoelastic interactions on the motion of the center of mass of a polymer as well as on the relaxation of Rouse modes, either in a Θ solvent or in a melt of identical unentangled chains. We show that this method allows us to describe the effect of hydrodynamic interactions beyond the Zimm (for a single chain in a Θ solvent) or the Rouse models (for an unentangled melt). In the latter case, we recover the same important effect of the viscoelastic hydrodynamic interactions on the center-of-mass diffusion, first described in Farago et al (2011 Phys. Rev. Lett. 107 178301).
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Affiliation(s)
- J Farago
- Institut Charles Sadron, Université de Strasbourg, CNRS UPR22, 22 rue du Loess, BP 84047, F-67034 Strasbourg, France.
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22
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Androulaki E, Vergadou N, Ramos J, Economou IG. Structure, thermodynamic and transport properties of imidazolium-based bis(trifluoromethylsulfonyl)imide ionic liquids from molecular dynamics simulations. Mol Phys 2012. [DOI: 10.1080/00268976.2012.670280] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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23
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Farago J, Semenov AN, Meyer H, Wittmer JP, Johner A, Baschnagel J. Mode-coupling approach to polymer diffusion in an unentangled melt. I. The effect of density fluctuations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:051806. [PMID: 23004780 DOI: 10.1103/physreve.85.051806] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Indexed: 06/01/2023]
Abstract
We quantitatively assess the effect of density fluctuation modes on the dynamics of a tagged polymer in an unentangled melt. To this end, we develop a density-based mode-coupling theory (dMCT) using the Mori-Zwanzig approach and projecting the fluctuating force onto pair-density fluctuation modes. The effect of dynamical density fluctuations on the center-of-mass (c.m.) dynamics is also analyzed based on a perturbative approach and we show that dMCT and perturbation techniques yield identical results. The c.m. velocity autocorrelation function (c.m. VAF) exhibits a slow power law relaxation in the time range between the monomer time t_{1} and the Rouse relaxation time t_{N}. We obtain an analytical expression for the c.m. VAF in terms of molecular parameters. In particular, the c.m. VAF scales as -N^{-1}t^{-5/4} (where N is the number of monomer units per chain) in the relevant time regime. The results are qualitatively accounted for by the dynamical correlation hole effect. The predicted -t^{-5/4} dependence of the c.m. VAF is supported by data of non-momentum-conserving computer simulations. However, the comparison shows that the theory significantly underestimates the amplitude of the effect. This issue is discussed and an alternative approach is addressed in the second part of this series [Farago et al., Phys. Rev. E 85, 051807 (2012), the following paper].
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Affiliation(s)
- J Farago
- Institut Charles Sadron, Université de Strasbourg, CNRS UPR22, 23 rue du Loess, 67034 Strasbourg Cedex 2, France
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Bormuth A, Henritzi P, Vogel M. Chain-Length Dependence of the Segmental Relaxation in Polymer Melts: Molecular Dynamics Simulation Studies on Poly(propylene oxide). Macromolecules 2010. [DOI: 10.1021/ma101721d] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. Bormuth
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - P. Henritzi
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
| | - M. Vogel
- Institut für Festkörperphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
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25
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Romanos NA, Theodorou DN. Crystallization and Melting Simulations of Oligomeric α1 Isotactic Polypropylene. Macromolecules 2010. [DOI: 10.1021/ma100677f] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Nikolaos A. Romanos
- School of Chemical Engineering, Department of Materials Science & Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zografou Campus, 157 80 Athens, Greece
| | - Doros N. Theodorou
- School of Chemical Engineering, Department of Materials Science & Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zografou Campus, 157 80 Athens, Greece
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26
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Williams G. Chain Dynamics in Solid Polymers and Polymerizing Systems as Revealed by Broadband Dielectric Spectroscopy. ACTA ACUST UNITED AC 2009. [DOI: 10.1002/masy.200951201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Logotheti G, Ramos J, Economou IG. Molecular Modeling of Imidazolium-Based [Tf2N−] Ionic Liquids: Microscopic Structure, Thermodynamic and Dynamic Properties, and Segmental Dynamics. J Phys Chem B 2009; 113:7211-24. [DOI: 10.1021/jp806999y] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Georgia−Evangelia Logotheti
- Molecular Thermodynamics and Modeling of Materials Laboratory, Institute of Physical Chemistry, National Center for Scientific Research “Demokritos”, GR-153 10 Aghia Paraskevi Attikis, Greece, and Department of Macromolecular Physics, Instituto de Estructura de la Materia - CSIC, Serrano 113bis, ES-28006, Madrid, Spain
| | - Javier Ramos
- Molecular Thermodynamics and Modeling of Materials Laboratory, Institute of Physical Chemistry, National Center for Scientific Research “Demokritos”, GR-153 10 Aghia Paraskevi Attikis, Greece, and Department of Macromolecular Physics, Instituto de Estructura de la Materia - CSIC, Serrano 113bis, ES-28006, Madrid, Spain
| | - Ioannis G. Economou
- Molecular Thermodynamics and Modeling of Materials Laboratory, Institute of Physical Chemistry, National Center for Scientific Research “Demokritos”, GR-153 10 Aghia Paraskevi Attikis, Greece, and Department of Macromolecular Physics, Instituto de Estructura de la Materia - CSIC, Serrano 113bis, ES-28006, Madrid, Spain
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Gitsas A, Floudas G. Pressure Dependence of the Glass Transition in Atactic and Isotactic Polypropylene. Macromolecules 2008. [DOI: 10.1021/ma8014992] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Gitsas
- Department of Physics, University of Ioannina, Post Office Box 1186, GR-45110 Ioannina, Greece, and Foundation for Research and Technology-Hellas (FORTH), Biomedical Research Institute (BRI), GR-71110 Heraklion, Crete, Greece
| | - G. Floudas
- Department of Physics, University of Ioannina, Post Office Box 1186, GR-45110 Ioannina, Greece, and Foundation for Research and Technology-Hellas (FORTH), Biomedical Research Institute (BRI), GR-71110 Heraklion, Crete, Greece
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Rissanou AN, Peristeras LD, Economou IG. Calculation of the effect of macromolecular architecture on structure and thermodynamic properties of linear–tri-arm polyethylene blends from Monte Carlo simulation. POLYMER 2007. [DOI: 10.1016/j.polymer.2007.04.066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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