FRACTAL CONFORMATION OF POLYMERS

Fractals ◽  
1993 ◽  
Vol 01 (02) ◽  
pp. 149-169 ◽  
Author(s):  
M. ADAM ◽  
D. LAIREZ
Keyword(s):  
Experimental Evidence ◽  
Star Polymers ◽  
Branched Polymers ◽  
Linear Polymers ◽  
Dilute Solutions ◽  
Theoretical Predictions

In this review, our purpose is to apply fractal concept to the description of the conformation of linear polymers, star polymers and branched polymers, in dilute and semi-dilute solutions in good solvent. Experimental evidence to theoretical predictions will be presented.

Problems in composing definitions of terms for polymer chemistry

Terminology ◽  
1995 ◽  
Vol 2 (2) ◽  
pp. 351-364 ◽  
Author(s):  
Aubrey D. Jenkins
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Branched Polymers ◽  
Polymer Chemistry ◽  
Linear Polymers ◽  
Dilute Solutions ◽  
International Union ◽  
Crystalline Polymers ◽  
Technical Terms

The particular problems associated with composing definitions of technical terms relating to polymers are outlined, and the way in which they have been tackled by the Commission on Macromolecular Nomenclature of the International Union of Pure and Applied Chemistry is described. The topics surveyed begin with basic terms and continue with linear polymers, branched polymers, and copolymers. The presentation of formulae, the description of stereochemistry, and definitions of terms for individual macromolecules, their assemblies and dilute solutions are included, as well as work on crystalline and liquid-crystalline polymers, and the classification of polymerisation processes.

scholarly journals Loss Aversion and Consumption Choice: Theory and Experimental Evidence

2015 ◽  
Vol 7 (2) ◽  
pp. 101-120 ◽  
Author(s):  
Heiko Karle ◽  
Georg Kirchsteiger ◽  
Martin Peitz
Keyword(s):  
Experimental Evidence ◽  
Loss Aversion ◽  
Consumer Choice ◽  
Rational Expectations ◽  
Choice Theory ◽  
Choice Model ◽  
Reference Points ◽  
Price Uncertainty ◽  
Theoretical Predictions

We analyze a consumer-choice model with price uncertainty, loss aversion, and expectation-based reference points. The implications of this model are tested in an experiment in which participants have to make a consumption choice between two sandwiches. Participants differ in their reported taste for the two sandwiches and in their degree of loss aversion, which we measure separately. We find that more-loss-averse participants are more likely to opt for the cheaper sandwich, in line with theoretical predictions. The estimates in the model with rational expectations are slightly more significant than those with naïve expectations. (JEL D11, D12, D84, M31)

scholarly journals Exploiting scaling laws for designing polymeric bottle brushes: a theoretical coarse-graining for homopolymeric branched polymers

2019 ◽  
Vol 21 (27) ◽  
pp. 14873-14878 ◽  
Author(s):  
Pietro Corsi ◽  
Elia Roma ◽  
Tecla Gasperi ◽  
Fabio Bruni ◽  
Barbara Capone
Keyword(s):  
Scaling Laws ◽  
Star Polymers ◽  
Coarse Graining ◽  
Branched Polymers ◽  
Coarse Grain ◽  
Multiscale Approach ◽  
Bottle Brushes

Scaling multiscale approach to coarse grain bottle brushes polymeric macromolecules as effective chains of tethered star polymers.

Synthesis and Properties of Regular Star Polybutadienes with 32 Arms

1992 ◽  
Vol 65 (2) ◽  
pp. 303-314 ◽  
Author(s):  
L-L. Zhou ◽  
N. Hadjichristidis ◽  
P. M. Toporowski ◽  
J. Roovers
Keyword(s):  
Molecular Weight ◽  
Coupling Agent ◽  
Hard Sphere ◽  
Star Polymers ◽  
Radius Of Gyration ◽  
Linear Polymers ◽  
Solution Properties ◽  
Mean Square ◽  
Dilute Solution ◽  
Dilute Solution Properties

Abstract A dendrimer carbosilane containing 32 Si—Cl bonds in the perimeter has been prepared and has been used as a coupling agent to prepare 32-arm star polybutadienes. The dilute-solution properties 〈RG2〉, A2, [η], and D0 have been measured in one good solvent and in one ¸ -solvent. The dimensions of the 32-arm star polymers are compared with those of linear polymers at constant molecular weight. It is shown that the 32-arm star polybutadiene has the characteristic properties of a hard-sphere molecule in dilute solution. The equivalent hard-sphere radii calculated from A2, D0 and [η] are identical and 1.29 times larger than the root mean-square radius of gyration. The Daoud—Cotton scaling model for stars is also tested.

Evaluating the Effect of Termination by Chain - Chain Coupling in Living Free-Radical Polymerizations

2003 ◽  
Vol 56 (8) ◽  
pp. 775 ◽  
Author(s):  
Jeffrey Pyun ◽  
Ian Rees ◽  
Jean M. J. Fréchet ◽  
Craig J. Hawker
Keyword(s):  
Free Radical ◽  
Star Polymers ◽  
Star Polymer ◽  
Direct Result ◽  
Vinyl Monomers ◽  
Linear Polymers ◽  
Radical Coupling ◽  
Novel Approach ◽  
Vis Spectroscopy ◽  
Radical Polymerizations

A novel approach based on the reaction of multifunctional star polymers with chromophore-labelled linear polymers is presented for evaluating the extent of termination by chain–chain coupling during living free-radical polymerizations. A mixed initiating system consisting of an unlabelled, multifunctional initiator and an excess of a monofunctional alkoxyamine initiator containing a chromophore, such as pyrene, is used to initiate the living polymerization of vinyl monomers leading to a mixture of star and linear polymers. The occurrence of chain–chain coupling is readily identified and quantified by isolating the star polymer that is obtained and elucidating the level of incorporation of pyrene units by UV/vis spectroscopy. This allows the level of chain–chain coupling to be determined since the inclusion of pyrene into the star structure is a direct result of termination by radical coupling.

scholarly journals Topological Disentanglement of Linear Polymers under Tension

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2580
Author(s):  
Michele Caraglio ◽  
Boris Marcone ◽  
Fulvio Baldovin ◽  
Enzo Orlandini ◽  
Attilio L. Stella
Keyword(s):  
Theoretical Description ◽  
Contour Length ◽  
Topological Invariants ◽  
Linear Polymers ◽  
Torus Knots ◽  
Semiflexible Polymer ◽  
Theoretical Predictions ◽  
Dynamics Simulations ◽  
Remarkable Agreement ◽  
Number Of Particles

We develop a theoretical description of the topological disentanglement occurring when torus knots reach the ends of a semiflexible polymer under tension. These include decays into simpler knots and total unknotting. The minimal number of crossings and the minimal knot contour length are the topological invariants playing a key role in the model. The crossings behave as particles diffusing along the chain and the application of appropriate boundary conditions at the ends of the chain accounts for the knot disentanglement. Starting from the number of particles and their positions, suitable rules allow reconstructing the type and location of the knot moving on the chain Our theory is extensively benchmarked with corresponding molecular dynamics simulations and the results show a remarkable agreement between the simulations and the theoretical predictions of the model.

Sign in / Sign up

Export Citation Format

Share Document