Dynamics of Polyethylene Melts, Studied by Monte-Carlo Methods

ORAL

Abstract

In connection with our diffusion measurements in polyethylene (PE) melts we have performed coarse-grained Monte-Carlo simulations on the second-nearest-neighbor diamond lattice to study static and dynamic properties of PE from C40 to C324 (molecular weight M from 584 to 4538). The bridging method is based on beads combining neighboring moieties and now uses two- bead moves; it permits detailed reconstruction of the PE chain at any stage. It uses the short-range rotational isomeric state model and inter- and intrachain Lennard-Jones potentials in their discretized forms. Simulation results become reliable after extended equilibration. For static properties such as the radius of gyration Rg the assumption of Gaussian chain statistics fails for all but the longest chains as Rg scales anomalously with M; at low M chain-end effects become important. But autocorrelation functions of the end-to-end vectors are still interpretable in terms of Rouse and reptation theories for chains longer than C82. Above C100 the relaxation times, converted from Monte-Carlo steps to time units by comparing with experimental diffusion (D) results, scale with M in keeping with reptation theory. At the lowest M, D has a slightly steeper M- dependence than experiment.

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Authors

  • Vishal Pandya

    Plasma Dynamics Corp., Department of Chemistry, University of Calabria, P. Bucci-15c, 87036 Rende (CS), ITALY, Air Force Institute of Technology, Gothenburg University, Sweden, Denison University, Department of Physics, University of Notre Dame, Department of Physics, John Carroll University, Department of Chemistry, The University of Akron, Department of Phyiscs, The University of Akron, Faculty of Chemical Technology, University of Pardubice, Czech Republic, Johns Hopkins University, Baltimore MD, Kent State University, Kent OH, University of Iowa, Physics Dept., Cleveland State University, Ohio State University, Rochester Institute of Technology, The Ohio State University, University of Akron, NASA Glenn Research Center, National Center For Space Exploration Research, Penn State College of Medicine, Department of Physics, Kent State University

  • Vishal Pandya

    Plasma Dynamics Corp., Department of Chemistry, University of Calabria, P. Bucci-15c, 87036 Rende (CS), ITALY, Air Force Institute of Technology, Gothenburg University, Sweden, Denison University, Department of Physics, University of Notre Dame, Department of Physics, John Carroll University, Department of Chemistry, The University of Akron, Department of Phyiscs, The University of Akron, Faculty of Chemical Technology, University of Pardubice, Czech Republic, Johns Hopkins University, Baltimore MD, Kent State University, Kent OH, University of Iowa, Physics Dept., Cleveland State University, Ohio State University, Rochester Institute of Technology, The Ohio State University, University of Akron, NASA Glenn Research Center, National Center For Space Exploration Research, Penn State College of Medicine, Department of Physics, Kent State University

  • Vishal Pandya

    Plasma Dynamics Corp., Department of Chemistry, University of Calabria, P. Bucci-15c, 87036 Rende (CS), ITALY, Air Force Institute of Technology, Gothenburg University, Sweden, Denison University, Department of Physics, University of Notre Dame, Department of Physics, John Carroll University, Department of Chemistry, The University of Akron, Department of Phyiscs, The University of Akron, Faculty of Chemical Technology, University of Pardubice, Czech Republic, Johns Hopkins University, Baltimore MD, Kent State University, Kent OH, University of Iowa, Physics Dept., Cleveland State University, Ohio State University, Rochester Institute of Technology, The Ohio State University, University of Akron, NASA Glenn Research Center, National Center For Space Exploration Research, Penn State College of Medicine, Department of Physics, Kent State University