Showing papers in "Computational and Theoretical Polymer Science in 1999"

TL;DR: In this article, a non-equilibrium method for calculating transport coefficients is presented, which reverses the experimental cause-and-effect picture, e.g. for the calculation of viscosities: the effect, the momentum flux or stress, is imposed, whereas the cause, the velocity gradient or shear rates, is obtained from the simulation.

TL;DR: In this article, the authors analyzed the effects of the caging process on the Rouse description of polymer melt dynamics, and showed that the typical time scale of the Rouse model reflects the onset of freezing as described by mode coupling theory.

TL;DR: In this paper, molecular dynamics simulations of water diffusion in a hydrated, amorphous polyamide have been carried out to study the effects of polymer dynamics, cross-linking, and hydrogen bonding interactions on the molecular mechanisms of diffusion.

TL;DR: In this article, the volumetric glass transition temperature has been determined as the temperature marking the discontinuity in slope of the V-T simulation data, based on the molecular mechanics force field used in this study.

TL;DR: In this article, a simulation of the interfaces, thin films and amorphous cells of several hydrocarbon polymers are studied with atomistic computer simulation, including polypropylene, polyethylenepropylene, and polyethylene-polypropylene.

TL;DR: In this article, a new approach to investigate free volume in atomistic simulation was devised, in which the atoms in the structure are represented by hard spheres and a phantom bubble is defined as an empty sphere, which contacts four or more hard spheres of atoms simultaneously in 3D space and does not overlap with any atom in the simulation.

TL;DR: In this article, a primitive molecular theory for stress-strain relationship of spherulitic polymers is presented based on a consideration of changes in conformational free energy in the tie chains and floating chains located between crystalline lamellae within an ideal spherula which is assumed to undergo an affine deformation.

TL;DR: In this paper, a poly(oxyethylene) (POE) chain with 15 ethylene oxide units in an aqueous solution in the presence of potassium cations for 1 ns was examined for the energetics, the hydration, the chain conformation and dynamics.

TL;DR: In this paper, the vibrational frequencies and intensities of octane, dodecane and hexadecane conformers have been calculated using quantum mechanical ab initio methods.

TL;DR: In this article, the most stable structures of various catalyst-cocatalyst systems were calculated by using molecular mechanics (MM) and molecular dynamics (MD), which are related to the space between central atoms of catalyst and cocatalyst, charges, and interaction energy were obtained from those structures.

TL;DR: In this paper, the authors numerically studied the transverse elastic behavior of a unidirectional composite comprising nonoverlapping silica fibers dispersed in a rubber matrix and identified some composite morphologies that provided an ultra high transverse shear modulus at rather moderate silica loadings.

TL;DR: In this article, a molecular dynamics based method for the generation and analysis of polymeric nano-particles is described, which is used to study the dynamics as well as the behavior and the structural, thermal, and mechanical properties of nano-meter scale polymer particles.

TL;DR: Both the eight-chain and the full network models can be closely approximated by an Edwards–Vilgis model, provided the finite chain extensibility limit is not approached too closely.

TL;DR: In this paper, the behavior of four derivative copolymers of poly(acrylic acid) were modeled in dilute aqueous polymer solutions with calcium counterions, and a specific Ca 2+ binding site sequence and geometry was identified as being responsible for the strong counterion binding.

TL;DR: In this article, the master equation for protein folding is solved numerically for a portion of Staphylococcal Protein A by a Laplace transformation and it is concluded that the native protein folds in a fast cooperative process.

TL;DR: In this article, a conformational analysis of some aromatic polyesters containing either an oxetane ring or propylene moieties in the main chain was performed using the Cerius2 program.

TL;DR: In this paper, the authors discussed the molecular mechanisms of rupture of simple crystalline solids, glassy polymers, and biological ligands and receptors, revealing similar behavior when these bonds are pulled apart at constant velocity, they rupture through a series of sudden yield events during which the material reorganizes.

TL;DR: In this article, an alternative approach based on the tube model of chain entanglements was found to provide a more accurate description of the experimental data, however, physical interpretation of the values for the model's parameters is problematic.

TL;DR: The potential energy landscape of a polymer glass with regard to plastic deformation under shear strain was examined in this article, where it was shown that the disappearance of local potential energy minima leads to irreversible deformation in polymer glasses.

TL;DR: In this paper, a kinetics model for the photopolymerization of furfuryl methacrylate in bulk based on the sensitivity analysis over a linear model is proposed.

TL;DR: In this article, a low-resolution virtual bond model for the protein structure is used with recently extracted knowledge-based potentials to identify potentially yielding or non-yielding regions of the protein for unfolding, in the kinetic sense, are identified from the correlation analysis of the rotational motions of the backbone bonds.

TL;DR: In this paper, the effect of copolymer sequence distribution and stiffness on the adsorption-desorption transition and configuration of an adsorbed polymer chain is examined by Monte Carlo methods.

TL;DR: The first algorithm for Brownian dynamics (BD) simulation of needle chains (the NC-algorithm) was developed recently by Nyland et al. as mentioned in this paper using N n rigid segments composed of N bn spherical beads, and its efficiency relative to the Ermak-McCammon BD algorithm (J. Chem. Phys. 1996;105:1198).

TL;DR: In this paper, structural properties of a fluid of hard sphere polymer chains about a variable sized central hard sphere were calculated using the Monte Carlo method in the canonical ensemble and an integral equation based on density functional theory.

TL;DR: In this article, the infrared and Raman spectra of polydichloro-phosphazene were calculated with the help of molecular dynamics methods; the spectral patterns were analyzed in relation to the bond conformations along the backbone.

TL;DR: In this article, the authors derived constitutive relations for the non-linear viscoelastic behavior of amorphous polymers subjected to physical aging, based on the concept of temporary networks, where the breakage and reformation rates depend on the current temperature and the configurational entropy, which is determined as a difference between the specific entropies of the equilibrium liquid and glass.

TL;DR: The probabilities of single and double contacts, and correlations among contacts were calculated for the random-flight model of a polymer chain, and the exact solution of the random flight model was used, so that the results are applicable also for residues which are relatively close to each other.

TL;DR: In this paper, an alternative methodology for the investigation of deformation properties of polymer glasses is presented, where the calculation of the stress-strain relation in simple extension is performed in the framework of a highly flexible lattice Monte Carlo algorithm.

TL;DR: In this paper, a framework was developed to provide an objective mechanism for incorporating the primary structural aspects of a polymer in predicting physical properties, especially mechanical and optical properties, of networks.

TL;DR: In this article, the authors used Monte Carlo integration to calculate the scaling exponent of the excluded volume of a polymer chain with another chain of the same length in the dilute solution regime.