Unperturbed Dimensions of Atactic Poly(phenylacetylene)

2005 ◽  
Vol 70 (11) ◽  
pp. 1787-1798 ◽  
Author(s):  
Dana Rédrová ◽  
Jan Sedláček ◽  
Majda Žigon ◽  
Jiří Vohlídal
Keyword(s):  
Molecular Weight ◽  
Random Coil ◽  
Radius Of Gyration ◽  
Dilute Solution ◽  
Chain Branching ◽  
Unperturbed Dimensions ◽  
Molecular Weight Dependence ◽  
Atactic Polystyrene ◽  
Tetrahydrofuran Solution ◽  
Insight Into

Dilute solution characteristics of atactic (ca. 30% trans) poly(phenylacetylene), PPA, were determined by using the SEC/MALS technique in order to obtain a deeper insight into discrepancy between presumed rigidity of conjugated polyvinylene molecules and their random-coil behavior in solutions resulting from earlier viscometry measurements. PPA was found to exhibit the molecular-weight dependence of the radius of gyration in tetrahydrofuran solution similar to that of atactic polystyrene (saturated analogue of PPA); also unperturbed dimensions of these polymers are almost equal. This rather surprising observation is explained as a consequence of the increased π-π attraction between highly polarizable PPA segments with well-delocalized π-electrons, which compensates the effect of stiffening of these segments due to conjugation. Possible influence of chain branching is also discussed.

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.

LIGHT-SCATTERING STUDIES ON ALUMINUM DISTEARATE

1958 ◽  
Vol 36 (11) ◽  
pp. 1584-1595 ◽  
Author(s):  
A. E. Leger ◽  
J. C. Hyde ◽  
H. Sheffer
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Intrinsic Viscosity ◽  
Benzene Solution ◽  
Unit Length ◽  
Random Coil ◽  
Linear Molecule ◽  
Radius Of Gyration ◽  
Average Unit ◽  
Scattering Study

A light-scattering study of aluminum distearate in dilute benzene solution suggests that it is a linear molecule of random coil shape. This is further substantiated by intrinsic viscosity – molecular weight data, the constancy of the ratio of the molecular weight to the square of the radius of gyration (Rg), the value of Φ in Flory's intrinsic viscosity – molecular weight relationship, and the close agreement between the theoretical and experimental results found for the unit length of the polymer chain. This average unit length has been calculated to be 4.46 Å.

Molecular Weight Dependence of the Optical Rotation of Poly((R)-1-deuterio-n-hexyl isocyanate) in Dilute Solution

1996 ◽  
Vol 29 (8) ◽  
pp. 2878-2884 ◽  
Author(s):  
Naoko Okamoto ◽  
Fumika Mukaida ◽  
Hong Gu ◽  
Yo Nakamura ◽  
Takahiro Sato ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Optical Rotation ◽  
Dilute Solution ◽  
Molecular Weight Dependence

Molecular weight dependence of the noncrystalline component in dilute-solution-grown trans-1,4-polybutadiene crystals

1982 ◽  
Vol 15 (2) ◽  
pp. 338-342 ◽  
Author(s):  
S. Tseng ◽  
W. Herman ◽  
Arthur E. Woodward ◽  
B. A. Newman
Keyword(s):  
Molecular Weight ◽  
Dilute Solution ◽  
Molecular Weight Dependence

scholarly journals MATHEMATICAL STATISTICS : AN APPLICATION BASED STATISTICS

2020 ◽  
Author(s):  
JAYDIP DATTA
Keyword(s):  
Analytical Chemistry ◽  
Molecular Weight ◽  
Experimental Finding ◽  
Polynomial Regression ◽  
Random Coil ◽  
Radius Of Gyration ◽  
Hydrodynamic Properties ◽  
Chemistry Teaching ◽  
Physico Chemical ◽  
Standard Software

The APPLICATION part to be noted as follows: 1. RANDOM COIL BIOPOLYMERS. 2. BACTERIAL GROWTH. 3. PHYSICO-CHEMICAL ANALYSIS / ANALYTICAL CHEMISTRY. It is an experimental finding between Physical Chemistry and Analytical Chemistry Teaching methods .CITATION -Datta, Jaydip & Chatterjee, S & Bhattacharya, T. (2015). HYDRODYNAMIC MODELLING OF BIOPOLYMERS : A CORRELATION APPRAOCH ( ISSN : 0020-3254 ). 87. 2016. 10.6084/m9.figshare.12167607. In the earlier work 1 by Datta et al the important hydrodynamic properties like radius of gyration (R g) and root mean square end to end separation (R rms) can be calculated through theknown value of molecular weight (M). The mathematical modelling was done by polynomial regression through a standard software like curve finder. The present work correlates the most important viscometric property , Diffusion coefficient (D) 2,3 with the same hydrodynamic properties like radius of gyration (R g) i.e. D (R g) of the biopolymers. It is expected that a bulky biopolymer of Random Coil with high molecular weight diffuse more slowly through a solvent than the Random Coil of low.

scholarly journals MOLECULAR SIZE AND CONFIGURATION OF CELLULOSE TRINITRATE IN SOLUTION

1958 ◽  
Vol 36 (6) ◽  
pp. 952-969 ◽  
Author(s):  
M. M. Huque ◽  
D. A. I. Goring ◽  
S. G. Mason
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Ethyl Acetate ◽  
Average Molecular Weight ◽  
Molecular Size ◽  
Random Coil ◽  
Radius Of Gyration ◽  
Molecular Weight Range ◽  
Scattering Measurements ◽  
The Relationship

Viscosity and light-scattering measurements were made on several fractions and two unfractionated samples of cellulose trinitrate. The samples were prepared from bleached ramie, unbleached ramie, and cotton linters. The solvents were acetone and ethyl acetate. Viscosity was measured in a multishear viscometer designed for the purpose. Light-scattering measurements were made in a Brice-Phoenix Light-scattering Photometer modified to accommodate a cell which could be ultracentrifuged.The range of molecular weight investigated was from 6.5 × 105 to 25.0 × 105 The relationship between the z-average mean-square radius of gyration, [Formula: see text] and the z-average molecular weight was approximately linear in both solvents. The ratio of [Formula: see text] (where [Formula: see text] is the value of [Formula: see text] in the unperturbed state) was found constant in acetone but to increase with [Formula: see text] in ethyl acetate. This indicated that, whereas in acetone random coil configuration was attained, a configurational transition occurred in ethyl acetate in the molecular weight range investigated.The value of the exponent a in the relationship between intrinsic viscosity and molecular weight was found to be lower than unity but approximately equal in both solvents.The significance of the experimental data is discussed.

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