Gyration-Radius Expansion Factor of Oligo- and Poly(α-methylstyrene)s in Dilute Solution

2001 ◽  
Vol 34 (18) ◽  
pp. 6402-6408 ◽  
Author(s):  
Masashi Osa ◽  
Yukiyoshi Ueno ◽  
Takenao Yoshizaki ◽  
Hiromi Yamakawa
Keyword(s):  
Gyration Radius ◽  
Dilute Solution ◽  
Expansion Factor

Collapse of a single polystyrene chain in dioctyl phthalate: Effect of molecular weight

1985 ◽  
Vol 50 (11) ◽  
pp. 2579-2587 ◽  
Author(s):  
Petr Štěpánek ◽  
Čestmír Koňák
Keyword(s):  
Molecular Weight ◽  
Linear Function ◽  
Universal Function ◽  
Dioctyl Phthalate ◽  
Dilute Solution ◽  
Expansion Factor ◽  
Temperature Variable ◽  
Factor Α ◽  
Reduced Temperature ◽  
Polymer Region

The use of a viscous solvent (dioctyl phthalate) made possible an investigation of the whole coil-globule transition of polystyrene chains in dilute solution. For values of the reduced temperature variable τ√M lower than - 230 the globular polymer region was observed in which the radius R and the molecular weight M are related by R ~ M1/3. The range of the Θ region where the expansion factor α is a linear function of τ√M was determined as -50 < τ√M < 50. It was shown that within the whole temperature range investigated the expansion factor is a universal function of the variable τ√M. The polymer dimensions at the Θ temperature are higher by some 15% in this solvent than in cyclohexane; also, the width of the transition region is much larger.

Second Virial Coefficient and Gyration-Radius Expansion Factor of Oligo- and Poly(α-methylstyrene)s near the ϑ Temperature

2004 ◽  
Vol 37 (6) ◽  
pp. 2240-2248 ◽  
Author(s):  
Tomoaki Kawaguchi ◽  
Masashi Osa ◽  
Takenao Yoshizaki ◽  
Hiromi Yamakawa
Keyword(s):  
Virial Coefficient ◽  
Second Virial Coefficient ◽  
Gyration Radius ◽  
Expansion Factor

Excluded-Volume Effects in Dilute Polymer Solutions. V. Butyl Rubber in Various Solvents

1975 ◽  
Vol 48 (4) ◽  
pp. 765-780
Author(s):  
T. Tsuji ◽  
H. Fujita
Keyword(s):  
Excluded Volume ◽  
Dilute Solution ◽  
Expansion Factor ◽  
Excluded Volume Effects ◽  
Dilute Polymer Solutions ◽  
Composite Curve ◽  
Factor Α ◽  
Fundamental Requirement ◽  
Two Parameter ◽  
Parameter Theory

Abstract It is a fundamental requirement of the two-parameter theory of linear homopolymers in dilute solution that the expansion factor α, and the interpenetration function Ψ depend only on the excluded-volume parameter z and that these functions are universal in the sense that their forms are independent of the chemical nature of the polymer and solvent as well as of the temperature. It follows immediately from the above requirement that the values of Ψ for different combinations of polymer, solvent, and temperature should form a single composite curve when plotted against αs.

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.

Interpretation of Preferential Adsorption Using Random Phase Approximation Theory

1995 ◽  
Vol 60 (10) ◽  
pp. 1641-1652 ◽  
Author(s):  
Henri C. Benoît ◽  
Claude Strazielle
Keyword(s):  
Approximation Theory ◽  
Random Phase Approximation ◽  
Virial Coefficient ◽  
Random Phase ◽  
Second Virial Coefficient ◽  
Solvent Mixture ◽  
Gyration Radius ◽  
Thermodynamic Quantities ◽  
Phase Approximation ◽  
Preferential Adsorption

It has been shown that in light scattering experiments with polymers replacement of a solvent by a solvent mixture causes problems due to preferential adsorption of one of the solvents. The present paper extends this theory to be applicable to any angle of observation and any concentration by using the random phase approximation theory proposed by de Gennes. The corresponding formulas provide expressions for molecular weight, gyration radius, and the second virial coefficient, which enables measurements of these quantities provided enough information on molecular and thermodynamic quantities is available.

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