Simulations for structural and dynamic properties of dense polymer systems

1992 ◽  
Vol 88 (13) ◽  
pp. 1707 ◽  
Author(s):  
Kurt Kremer ◽  
Gary S. Grest
Keyword(s):  
Dynamic Properties ◽  
Polymer Systems

The Role of Filler Networking in Dynamic Properties of Filled Rubber

1999 ◽  
Vol 72 (2) ◽  
pp. 430-448 ◽  
Author(s):  
Meng-Jiao Wang
Keyword(s):  
Dynamic Properties ◽  
Cyclic Strain ◽  
Considerable Change ◽  
Dynamic Strain ◽  
Additional Energy ◽  
Polymer Systems ◽  
Filled Rubber ◽  
Filler Network ◽  
The Impact

Abstract Fillers, when added to polymer systems, are known to cause a considerable change in dynamic properties. For a given polymer and cure system, this paper discusses the impact of the filler network, both its strength and architecture, on the dynamic modulus and hysteresis during dynamic strain. It was found that the filler network can substantially increase the effective volume of the filler due to rubber trapped in the agglomerates, leading to high elastic modulus. The amount of trapped rubber was estimated according to Van der Poel theory. During cyclic strain, while the stable filler network can reduce the hysteresis of the filled rubber, the breakdown and reformation of the filler network would cause an additional energy dissipation resulting in higher hysteresis.

Diffusion of Confined Polymer Chains

2005 ◽  
Vol 237-240 ◽  
pp. 169-174 ◽  
Author(s):  
Andrzej Sikorski
Keyword(s):  
Dynamic Properties ◽  
Polymer Chains ◽  
Polymer Systems ◽  
Cubic Lattice ◽  
Simple Cubic ◽  
Simple Cubic Lattice ◽  
Simple Lattice ◽  
The Monte Carlo Method ◽  
A Chain ◽  
Confined Polymer Chains

Simple lattice model of polymer systems was developed and studied using the Monte Carlo method. The model chains were star-branched with f = 3 arms and rings. The number of polymer segments in a chain was varied up to 800. The chains were built on a simple cubic lattice with the excluded volume interactions only (the athermal system). The polymers were confined between two parallel impenetrable walls with a set of irregular obstacles what can be treated as porous media. A Metropolis-like sampling algorithm employing local changes of chain conformation was used. The dynamic properties of the model system were studied. The differences in the mobility of chains with different internal architectures were shown and discussed. The possible mechanisms of motions were presented.

Untangling the mechanics of entanglement in slide-ring gel towards both super-deformability and toughness

Soft Matter ◽  
2022 ◽  
Author(s):  
Ziyu Xing ◽  
Dong-Wei Shu ◽  
Haibao Lu ◽  
Yong Qing Fu
Keyword(s):  
Large Deformation ◽  
Dynamic Properties ◽  
Critical Role ◽  
High Strength ◽  
Polymer Systems

Entanglement plays a critical role in determining dynamic properties of polymer systems, e.g., resulting in slip links and pulley effects for achieving their large deformation and high strength. Although it...

Accelerator Systems for Injection Molding

1982 ◽  
Vol 55 (2) ◽  
pp. 494-512 ◽  
Author(s):  
W. W. Paris ◽  
J. R. Dillhoefer ◽  
W. C. Woods
Keyword(s):  
High Temperature ◽  
Injection Molding ◽  
Dynamic Properties ◽  
Tensile Modulus ◽  
Polymer Systems ◽  
Compression Set ◽  
Cure Time ◽  
Injection Molded ◽  
The Subject ◽  
Ozone Resistance

Abstract A reciprocating screw injection press has been used to evaluate various accelerator combinations in NR, SBR, EPDM, and NBR. A laboratory mold was used which includes a 75 mm × 125 mm × 2 mm sheet, three molded dumbbells (size Die C), a compression pellet and a Goodrich Flexometer pellet. The total volume of the mold is approximately 85 cm3. Those observations have confirmed that the following relationships exist for high temperature vulcanization, particularly in an injection press. (1) Tensile modulus is reduced at higher curing temperatures for all four polymer systems. (2) In NR and SBR, it is possible to obtain moduli at high temperature comparable to moduli at lower temperatures by increasing the accelerator level while maintaining a constant sulfur concentration. (3) There is a correlation between rheometer cure time (t90) and injection molding cure times. The correlation is good enough to rank the cure time of various stocks, but not good enough to predict cure times. (4) Injection molded stocks consistently exhibit a lower hardness when compared with stocks compression molded at the same temperature. (5) Injection molded dumbbells produce higher ultimate tensile strength than do die-cut specimens. (6) With few exceptions (i.e., very scorchy stocks), the injection moldability of a stock is not dependent upon the vulcanization system used. (7) Even with NR, rather large variations in injection molding times produce only small changes in initial physical properties. The effects of injection molding and it's variables on compression set, dynamic properties, aging characteristics, fatigue life, and ozone resistance remain unanswered and should be the subject of further evaluations.

The distribution of antigen on the surface of RBL-2H3 rat basophilic leukemia cells observed by back-scattered electron imaging

1986 ◽  
Vol 44 ◽  
pp. 274-275
Author(s):  
R.F. Stump ◽  
J.R. Pfeiffer ◽  
JC. Seagrave ◽  
D. Huskisson ◽  
J.M. Oliver
Keyword(s):  
Cell Surface ◽  
Dynamic Properties ◽  
Leukemia Cells ◽  
Antigen Binding ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Rat Basophilic Leukemia Cells ◽  
Electron Imaging ◽  
Basophilic Leukemia

In RBL-2H3 rat basophilic leukemia cells, antigen binding to cell surface IgE-receptor complexes stimulates the release of inflammatory mediators and initiates a series of membrane and cytoskeletal events including a transformation of the cell surface from a microvillous to a lamellar topography. It is likely that dynamic properties of the IgE receptor contribute to the activation of these responses. Fewtrell and Metzger have established that limited crosslinking of IgE-receptor complexes is essential to trigger secretion. In addition, Baird and colleagues have reported that antigen binding causes a rapid immobilization of IgE-receptor complexes, and we have demonstrated an apparent increase with time in the affinity of IgE-receptor complexes for antigen.

Structure-property relationships of PE/PP sandwiched films

1987 ◽  
Vol 45 ◽  
pp. 454-455
Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi
Keyword(s):  
Mechanical Tests ◽  
Polymer Materials ◽  
Ionic Crystals ◽  
Structure Property ◽  
Polymer Systems ◽  
Structure Property Relationships ◽  
Oriented Films ◽  
Materials Used ◽  
Polymer Laminates ◽  
Heated Glass

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.

Approaches for TEM imaging of cavitation in toughened nylon

1989 ◽  
Vol 47 ◽  
pp. 352-353
Author(s):  
Barbara A. Wood
Keyword(s):  
Morphological Characteristics ◽  
Structure Property ◽  
Polymer Systems ◽  
Selective Staining ◽  
Structure Property Relationships ◽  
Rubber Toughened ◽  
Shear Yield ◽  
Controversial Topic ◽  
Selection Of ◽  
Diamond Knife

A controversial topic in the study of structure-property relationships of toughened polymer systems is the internal cavitation of toughener particles resulting from damage on impact or tensile deformation.Detailed observations of the influence of morphological characteristics such as particle size distribution on deformation mechanisms such as shear yield and cavitation could provide valuable guidance for selection of processing conditions, but TEM observation of damaged zones presents some experimental difficulties.Previously published TEM images of impact fractured toughened nylon show holes but contrast between matrix and toughener is lacking; other systems investigated have clearly shown cavitated impact modifier particles. In rubber toughened nylon, the physical characteristics of cavitated material differ from undamaged material to the extent that sectioning of heavily damaged regions by cryoultramicrotomy with a diamond knife results in sections of greater than optimum thickness (Figure 1). The detailed morphology is obscured despite selective staining of the rubber phase using the ruthenium trichloride route to ruthenium tetroxide.

Nucleosome dynamics

2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  
Keyword(s):  
High Resolution ◽  
Chromatin Structure ◽  
Current Knowledge ◽  
Dynamic Properties ◽  
Structure And Dynamics ◽  
Nucleosome Dynamics ◽  
Sharp Focus ◽  
Recent Advances ◽  
Insight Into ◽  
Chromatin Structure And Dynamics

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.

Interactions between citrate and montmorillonite-Al hydroxide polymer systems

1997 ◽  
Vol 48 (3) ◽  
pp. 463-472 ◽  
Author(s):  
R.P.T. JANSSEN ◽  
M.G.M. BRUGGENWERT ◽  
W.H. VAN RIEMSDIJK
Keyword(s):  
Polymer Systems

Nonlinear Thermodynamic Relaxation in Living Polymer Systems

1991 ◽  
Vol 1 (5) ◽  
pp. 489-492 ◽  
Author(s):  
C. M. Marques ◽  
M. E. Cates
Keyword(s):  
Polymer Systems
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