Showing papers in "Computational and Theoretical Polymer Science in 1997"

TL;DR: In this article, a simple scaling derivation of the non-affine deformation of the lateral tube dimension is presented based on an affine-coupling-hypothesis of network strands between successive entanglements.

TL;DR: In this paper, molecular dynamics simulations of the thermal degradation of polymer nanocomposites were performed in an attempt to explain the reduction in the flammability of these materials, as compared to the pure polymer, that has been observed in experimental measurements.

TL;DR: In this article, computer simulation techniques such as Monte Carlo methods, molecular mechanics and molecular dynamics are reviewed, and detailed information about the arrangement of molecules and chain segments in relation to the macroscopic behaviour of the materials could be obtained using these simulation techniques.

TL;DR: In this article, the surface energy of very thin polyethylene was studied and the contribution of the internal energy to the surface of the poly(1,4- cis-butadiene) was estimated to be 20 erg cm −2, which is lower than the experimental value of 26 erg cm−2 reported in the literature.

TL;DR: In this article, a quantitative structure-property relationship (QSPR) model was constructed to predict O 2, N 2 and CO 2 diffusion in amorphous polymers.

TL;DR: In this paper, all compact self-avoiding walks on the square and the cubic lattice within simple geometries were generated and enumerated for all possible combinations of l, m, n, n, l, m, n and n of a parallelepiped of size l × m × n.

TL;DR: In this article, the authors show that the segmental relaxation function broadens with increasing crosslink density, accompanied by a larger activation energy, and a heightened sensitivity to temperature (larger activation energy) is observed.

TL;DR: In this paper, a statistical thermodynamic theory is presented with a new approach to account for the mixing of polymers, small molecules, and holes, which are different in size, and the criterion for glass transition is taken to be the vanishing of entropy pertaining to the non-local movements of polymer segments rather than the total mixing entropy of the system.

TL;DR: In this article, a conformational analysis of polyethers containing the oxetanic ring in the main chain was performed using the Cerius 2 program (version 2.0) molecular simulation software for material science.

TL;DR: A critical inspection of experimental data on the osmotic modulus reveals that universal laws can be formulated also for branched macromolecules in solution, at least up to the overlap concentration c * .

TL;DR: In this article, potentials developed earlier for crystalline and amorphous bulk PEO systems have been used for the MD simulation of a PEO surface model, which comprises the outer region of a 122 Angstrom-thi...

TL;DR: In this article, a numerical model with finite differences is built, taking into account the heat transfer by conduction through the polymers and by convection at the external surface, and the diffusion of the contaminant through the polymer layers with a temperature-dependent diffusivity.

TL;DR: In this article, the collapse-transition of a polyethylene-chain was investigated using a united-atom model starting from a perfectly aligned all-trans conformation, and various chain lengths, temperatures, initial velocity-distributions and van-der-Waals potentials were considered.

TL;DR: In this article, a theoretical scheme with due considerations on the formation of intramolecular cycles is developed for polycyanate networks, based on the recursive method of Macosko and Miller.

TL;DR: In this article, a polyethylene chain (980 CH2) changed its overall shape from an isotropic coil to an oriented one nearly normal to the substrate surface of amorphous carbons at 200, 300, 400 and 500 k.

TL;DR: In this paper, the authors simulated chain collapse and ionic aggregation of sodium salts of lightly sulphonated polystyrene (Na-SPS) in a poor solvent by molecular dynamics of a single ionomer chain.

TL;DR: In this paper, the relativistic effective core potential calculation was carried out to numerically characterize the comparative adhesion properties of polymers with different types of metal surfaces, and the nature of the interactions were investigated by computing potential energy surfaces, electron populations and orbital energies of systems of interest.

TL;DR: In this article, various thermodynamic equations for axially deformed perfect fibres of finite molecular weight polymers were derived using the characteristic state of stress-induced fusion (melting) as a point of reference.

TL;DR: In this article, the authors used Monte Carlo simulations to compute the scattering form factor S(q) of regular polymer star chains of different numbers of arms as a function of the scattering variable q. The simulation conditions correspond to good solvent solutions at different concentrations, and isolated chains in solvents of different thermodynamic qualities.

TL;DR: In this article, the structural difference of the interface between polypropylene pair (PP/PP) and poly propylene and poly(ethylene-alt-propylene) pair was investigated using molecular dynamics and molecular mechanics, under a two-dimensional periodic boundary condition (2DPBC).

TL;DR: In this paper, a simple model for the free energy associated with the relaxation of a linear chain polymer melt is considered, and it is shown that the extent of relaxation decreases as the length scale for relaxation increases.

TL;DR: In this paper, the single crystal stiffness constants of different structures of syndiotactic polypropylene have been calculated using a molecular modelling package, which has been used to predict some mechanical properties of a uniaxially aligned aggregate of crystals.

TL;DR: In this paper, the authors used nonlinear least squares (NLLS) curve fitting to fit the theoretical equations of the (1) terminal, (2) penultimate unit effect, (3) complex participation, (4) complex dissociation and (5) comppen copolymerisation models to the experimental data of the triad mole fractions (F 010, F (011+110), F 111 ) and the copolymers composition (F 0 ).

TL;DR: In this article, Monte Carlo simulations were done to predict the rate of domain growth in an amphiphilic system and an Ising-type model was used for a system comprised of two homopolymers A and B and the corresponding copolymer A-B. The model is fast from a computational viewpoint.

TL;DR: In this article, the authors used steady state fluorescence depolarization measurements in a solid matrix of poly(methyl methacrylate) and molecular dynamics calculations were used to study the efficiency of intramolecular nonradiative singlet energy transfer between naphthalene groups in trichromophoric model compounds.

TL;DR: In this paper, the influence of external deformation on the microphase separation in IPNs was studied based on the random phase approximation and classical Landau-Ginzburg theory, which can be explained as a coupling between a network chain interaction and the effect of irreversibly closed crosslinks.

TL;DR: In this article, the authors discussed the implications of contractile networks for cell cytoskeletons for unidirectional migration in anisotropic networks changing periodically or randomly their internal structures.

TL;DR: In this article, the combination of an Ising model with antiferromagnetic interaction and the neighbour-facilitated Fredrickson-Anderson model allows a description of the polarization decay of polarized materials below the glass temperature Tg.

TL;DR: In this paper, the results from the numerical simulation of the polarization decay below the glass transition of the neighbor facilitated Fredrikson-Anderson model and the results of polarization decay in the copolymer poly(MMA-co-PAMEE) were compared.