Insensitivity of Sterically Defined Helical Chain Conformations to Solvent Quality in Dilute Solution

2020 ◽  
Vol 9 (6) ◽  
pp. 849-854
Author(s):  
Beihang Yu ◽  
Scott P. O. Danielsen ◽  
Kai-Chieh Yang ◽  
Rong-Ming Ho ◽  
Lynn M. Walker ◽  
...  
Keyword(s):  
Helical Chain ◽  
Dilute Solution ◽  
Solvent Quality ◽  
Chain Conformations

Non-Helical Chain Conformations of Isotactic Polymers in the Crystalline State

2004 ◽  
Vol 205 (3) ◽  
pp. 390-396 ◽  
Author(s):  
Finizia Auriemma ◽  
Claudio De Rosa ◽  
Paolo Corradini
Keyword(s):  
Crystalline State ◽  
Helical Chain ◽  
Chain Conformations

scholarly journals Modeling short-chain branched polyethylenes in dilute solution under variable solvent quality conditions: Basic configurational properties

Polymer ◽  
2021 ◽  
Vol 217 ◽  
pp. 123429
Author(s):  
Wengang Zhang ◽  
Fernando Vargas-Lara ◽  
Sara V. Orski ◽  
Kathryn L. Beers ◽  
Jack F. Douglas
Keyword(s):  
Short Chain ◽  
Dilute Solution ◽  
Solvent Quality

scholarly journals Modeling short-chain branched polyethylenes in dilute solution under variable solvent quality: Basic configurational properties

2021 ◽  
Author(s):  
Wengang Zhang ◽  
Fernando Vargas-Lara ◽  
Sara Orski ◽  
Kathryn Beers ◽  
Jack Douglas
Keyword(s):  
Short Chain ◽  
Dilute Solution ◽  
Solvent Quality

scholarly journals Специфика статистики упругих и деформационно-прочностных свойств высокопрочных волокон полипропилена

2022 ◽  
Vol 64 (1) ◽  
pp. 85
Author(s):  
Ю.М. Бойко ◽  
В.А. Марихин ◽  
О.А. Москалюк ◽  
Л.П. Мясникова
Keyword(s):  
Polymeric Materials ◽  
High Strength ◽  
Polyamide 6 ◽  
Chain Conformation ◽  
Helical Chain ◽  
Statistical Distributions ◽  
Single Fibers ◽  
Weibull Models ◽  
Chain Conformations ◽  
Ultra High Molecular Weight

Regularities of statistical distributions of a complex of mechanical properties, including the module of elasticity (E), strength () and strain at break (b), high-strength industrial oriented polypropylene (PP) fibers have been analyzed using the Weibull and Gauss models based on large a wide array of measurements (50 identical samples in each series). The values of the statistical Weibull modulus (m) - a parameter characterizing the scatter of the measured values of the data arrays of E,  and b – have been estimated for the PP samples of two types: single fibers (monofilaments) and multifilament fibers consisting from several hundred single fibers. For the PP multifilament fibers, a more correct description of the distributions of E,  and b has been received both in the framework of the normal distribution (Gaussian distribution) and in the framework of the Weibull distribution in comparison with the description of such distributions for the PP monofilaments. The influence of the polymer chain conformation on the regularities of the statistical distributions of E,  and b for the high-strength oriented polymeric materials with different chemical chain structures and the correctness of their descriptions in the framework of the Gauss and Weibull models have been analyzed. For this purpose, the values of m calculated in this work for PP with a helical chain conformation have been compared with the values of m determined by us earlier for ultra-high molecular weight polyethylene and polyamide-6 with the chain conformations in the form of an in-plane trans-zigzag.

scholarly journals Unusual Structures of Interpolyelectrolyte Complexes: Vesicles and Perforated Vesicles

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 871 ◽  
Author(s):  
A. A. Glagoleva ◽  
D. E. Larin ◽  
V. V. Vasilevskaya
Keyword(s):  
Electrostatic Interactions ◽  
Spherical Particles ◽  
Dilute Solution ◽  
Solvent Quality ◽  
Theoretical Approaches ◽  
Interpolyelectrolyte Complexes ◽  
Different Shapes ◽  
Spherical Harmonics Expansion ◽  
Good Agreement ◽  
Poor Solvent

By means of computer simulation and analytical theory, we first demonstrated that the interpolyelectrolyte complexes in dilute solution can spontaneously form hollow spherical particles with thin continuous shells (vesicles) or with porous shells (perforated vesicles) if the polyions forming the complex differ in their affinity for the solvent. The solvent was considered good for the nonionic groups of one macroion and its quality was varied for the nonionic groups of the other macroion. It was found that if the electrostatic interactions are weak compared to the attraction induced by the hydrophobicity of the monomer units, the complex in poor solvent tends to form “dense core–loose shell” structures of different shapes. The strong electrostatic interactions favor the formation of the layered, the hollow, and the filled structured morphologies with the strongly segregated macroions. Vesicles with perforated walls were distinguished as the intermediate between the vesicular and the structured solid morphologies. The order parameter based on the spherical harmonics expansion was introduced to calculate the pore distribution in the perforated vesicles depending on the solvent quality. The conditions of the core–shell and hollow vesicular-like morphologies formation were determined theoretically via the calculations of their free energy. The results of the simulation and theoretical approaches are in good agreement.

Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

1987 ◽  
Vol 45 ◽  
pp. 388-389
Author(s):  
P. Pradère ◽  
J.F. Revol ◽  
R. St. John Manley
Keyword(s):  
Low Dose ◽  
Polymer Concentration ◽  
Processing System ◽  
Limiting Factor ◽  
Dilute Solution ◽  
New Techniques ◽  
Dose Unit ◽  
Lattice Images ◽  
Dose Imaging ◽  
Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

Two-stage self-seeding method for preparation of single crystals of poly(phenylene sulfide)

1989 ◽  
Vol 47 ◽  
pp. 368-369
Author(s):  
Sengshiu Chung ◽  
Peggy Cebe
Keyword(s):  
Single Crystals ◽  
High Performance ◽  
Dilute Solution ◽  
Two Stage ◽  
Annealing Behavior ◽  
High Performance Polymers ◽  
Seeding Method ◽  
Phenylene Sulfide

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.

Effect of Solvent Quality on the Behaviour of Highly Charged Polyelectrolytes

1995 ◽  
Vol 5 (9) ◽  
pp. 1269-1275 ◽  
Author(s):  
W. Essafi ◽  
F. Lafuma ◽  
C. E. Williams
Keyword(s):  
Effect Of Solvent ◽  
Solvent Quality
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