Macromolecular Theory and Simulations

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Early View (Online Version of Record published before inclusion in an issue)

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  1. Full Paper

    1. Temperature Dependence of Structural Properties and Chain Configurational Study: A Molecular Dynamics Simulation of Polyethylene Chains

      Haifeng Lu, Zhiping Zhou, Tongfan Hao, Xubo Ye and Yijing Ne

      Article first published online: 3 APR 2015 | DOI: 10.1002/mats.201500007

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      Micro-structural evolution of polyethylene across the glass transition temperature is investigated by full atom molecular dynamic simulation. The relationship between the specific volume and the temperature can be used to determine glass temperature of amorphous polyethylene system. The dihedral distribution of the overall bonds of the amorphous polyethylene chain system keeps consistent with the rotational isomeric state scheme. The dependence of isomer probability of skeletal bonds and average radius of gyration on temperature also can be used to estimate the glass temperature.

  2. Communications

    1. A Cross-Linking Copolymerization Mathematical Model Including Phase Separation and Cyclization Kinetics

      Leandro G. Aguiar

      Article first published online: 1 APR 2015 | DOI: 10.1002/mats.201500018

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      The gelation dynamics is modeled through the Numerical Fractionation technique, which is applied for gel and sol phases (the numbers represent the chain generations). The cyclization reactions' rate depends on the degree of polymerization and on the good/poor solvent mixture's composition. These reactions are responsible for delaying the gelation process, affecting the porosity of the polymer particle, as shown in simulation results.

  3. Full Papers

    1. Analysis of Advective–Diffusive Transport in Complex Mixing Devices by the Diffusive Mapping Method

      Oleksandr Gorodetskyi, Iaroslav Vivat, Michel F. M. Speetjens and Patrick D. Anderson

      Article first published online: 1 APR 2015 | DOI: 10.1002/mats.201400083

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      Mixing in realistic industrial devices is of great relevance. The diffusive mapping method is a flexible technique for mixing simulations inside complex geometries. This study applies this method to advective–diffusive transport in two prototypical 3D industrial mixers. It is combined with the extended finite element method (XFEM), enabling reliable and efficient computation of evolving concentration fields.

  4. Communications

    1. New Structural Model of PANI/CSA Conducting Polymer System Obtained by Molecular Dynamics Simulations

      Maciej Śniechowski, Remigiusz Borek, Konrad Piwowarczyk and Wojciech Łużny

      Article first published online: 31 MAR 2015 | DOI: 10.1002/mats.201400105

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      The structure of polyaniline protonated with camphorsulfonic acid has been modeled by molecular dynamics simulations. All partial charges have been derived from DFT quantum calculations and a new force field has been applied. The resulting stable structure is characterized by double layers of PANI separated by double layers of CSA. The new model is in good agreement with several experimental data.

  5. Full Papers

    1. Realistic Representation of Kinetics and Microstructure Development During Chain Shuttling Polymerization of Olefin Block Copolymers

      Mostafa Ahmadi and Amin Nasresfahani

      Article first published online: 25 MAR 2015 | DOI: 10.1002/mats.201500004

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      An effective model is developed for representation of kinetics and microstructure evolution in the course of chain shuttling polymerization in the view of both OBC chains and individual hard and soft blocks.

    2. Modeling of Branching Distributions in Butyl Acrylate Polymerization Applying Monte Carlo Methods

      Marco Drache, Benjamin Hosemann, Tetyana Laba and Sabine Beuermann

      Article first published online: 23 FEB 2015 | DOI: 10.1002/mats.201400081

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      The Monte Carlo (MC) simulator mcPolymer is capable of handling of a large number of molecules, allowing for the implementation of a chain-length-dependent termination model. It was applied to the complex kinetic model of butyl acrylate polymerizations, being able to reproduce experimental findings. Furthermore, detailed information on the microstructure of each individual polymer chain was extracted.

    3. Kinetic Model of the Amphiphilic Copolymers with Hyperbranched Core Formed by AB2 Monomer and Bf Initiator

      Zhiping Zhou, Tongfan Hao and Deyue Yan

      Article first published online: 14 FEB 2015 | DOI: 10.1002/mats.201400102

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      The kinetic model of the amphiphilic copolymers with hyperbranched core and linear arms was developed. The molecular size distribution functions of the species obtained were analytically derived. Accordingly, the topological structures of the amphiphilic hyperbranched copolymers and the successive self-assembly shapes can be designed.

    4. Comparison of Crosslinking Algorithms in Molecular Dynamics Simulation of Thermosetting Polymers

      Changwoon Jang, Timothy W. Sirk, Jan W. Andzelm and Cameron F. Abrams

      Article first published online: 29 JAN 2015 | DOI: 10.1002/mats.201400094

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      MD simulations with ad-hoc cross-linking algorithms have been used to generate molecular models of fully cross-linked epoxy materials. Two such algorithms are compared, and it is shown that glassy-state thermal and mechanical properties were not significantly influenced by the algorithm choice. This result notwithstanding, it is shown that the two algorithms result in very different network isomers, pointing toward a possible experimental method of structure validation in future work.

    5. Step-Growth Polymerized Systems of General Type “AfiBgi”: Generating Functions and Recurrences to Compute the MSD

      L. Tom Hillegers and Johan J. M. Slot

      Article first published online: 29 JAN 2015 | DOI: 10.1002/mats.201400091

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      From the recipe straight to the MSD. For step-growth polymerized systems of general type “AfiBgi”, a computer algebra method is presented that leads via a few transformation steps from the recipe to the MSD.

    6. Modeling of Catalyzed Chain Growth (CCG) Polymerization of Styrene-d8 using Cp*2ZrCl2 and Dibenzylmagnesium

      Sebastian Primpke and Philipp Vana

      Article first published online: 23 JAN 2015 | DOI: 10.1002/mats.201400087

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      A kinetic scheme describing Catalytic Chain Growth (CCG) polymerization was developed and implemented into the computer program PREDICI, by which experimental concentration versus time traces of the participating individual species obtained from online NMR spectroscopy as well as full molecular weight distributions could successfully be modeled. The method was demonstrated on the CCG of styrene-d8 in toluene-d8 using Cp*2ZrCl2 as the catalyst precursor and dibenzyl magnesium as the transfer agent.

    7. A Quantum Mechanical Study on the Propagation Kinetics of N-methylacrylamide: Comparison With N,N-Dimethylacrylamide in Free Radical Polymerization

      Gülru Kayık and Nurcan Ş. Tüzün

      Article first published online: 13 JAN 2015 | DOI: 10.1002/mats.201400096

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      Propagation kinetics in free radical polymerization of N,N-dimethylacrylamide and N-methylacrylamide is modeled with quantum chemical calculations at dimeric model stage. The propagation rate constant ratio of these monomers is calculated with various density functionals. Calculations shed light on the electronic and steric effects and hydrogen bonding interactions within the reactive species that co-play a role in determining the favorable modes of additions.

    8. On the Relationship Between Plateau Modulus and Shear Relaxation Time in Transient Networks

      Ana West and James T. Kindt

      Article first published online: 8 JAN 2015 | DOI: 10.1002/mats.201400093

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      A simple equation relating the microscopic lifetime of associating chains in a transient network to the shear stress relaxation time, in terms of the concentration dependence of the plateau modulus, is proposed and tested against published experimental data on associating polymers near the gelation transition and against simulated networks well above the gelation transition.

    9. Orientation in Large-Amplitude Oscillatory Shear

      A. M. Schmalzer and A. J. Giacomin

      Article first published online: 29 DEC 2014 | DOI: 10.1002/mats.201400058

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      We examine the simplest relevant molecular model for large-amplitude oscillatory shear flow of a polymeric liquid: the dilute suspension of rigid dumbbells in a Newtonian solvent. We find explicit analytical expressions for the orientation distribution, and use these expressions to examine the detailed shape of the orientation distribution with detailed visualizations all the way around one full alternant cycle.

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