Computer experiments on branched-chain molecules

1982 ◽  
Vol 15 (2) ◽  
pp. 660-664 ◽  
Author(s):  
Kanji Kajiwara ◽  
Walther Burchard
Keyword(s):  
Computer Experiments ◽  
Chain Molecules ◽  
Branched Chain

Structures and properties of mixtures of branched chain compounds and lecithin: phytol, α-tocopherol (vitamin E), and phytanic acid

1979 ◽  
Vol 57 (4) ◽  
pp. 458-465 ◽  
Author(s):  
Robert J. Cushley ◽  
Bruce J. Forrest ◽  
Anne Gillis ◽  
Jenifer Tribe
Keyword(s):  
Differential Scanning Calorimetry ◽  
Vitamin E ◽  
Phytanic Acid ◽  
Liquid Crystalline ◽  
Egg Yolk ◽  
Scanning Calorimetry ◽  
Chain Molecules ◽  
Structures And Properties ◽  
Branched Chain ◽  
Crystalline Phase Transition

Phospholipid bilayers containing branched chain molecules, phytol (1), vitamin E (2), and phytanic acid (3), have been investigated by 31P nmr, esr, and differential scanning calorimetry (dsc).A 31P lanthanide induced shift study indicated varying permeabilities to Pr3+ in the order phytanic acid > vitamin E > phytol > egg yolk lecithin alone; the half-lives (in days) were 0.002, 0.14, 0.83, and 6.5, respectively. The activation energy for Pr3+ permeation through the egg yolk lecithin–phytol membrane was found to be 84.9 ± 0.8 kJ.The following esr order parameters, S3, were obtained using the extrinsic spin label, 5-doxylpalmitic acid, in oriented mixed multibilayers: S3 (1) = 0.29, S3 (2) = 0.50, and S3 (3) = 0.02.Differential scanning calorimetry revealed a lowering of the gel–liquid crystalline phase transition temperature, Tc, as the concentration of incorporated isoprenoid compound increases, with eventual disappearance of the endotherm. Specific entropy, s, calculated for dipalmitoyl lecithin +25 mol% 3 is 126 J kg−1 K−1 compared to s = 114.2 J kg−1 K−1 for 1and s = 85 J kg−1 K−1 for 2.

Statistical Mechanics of High Polymer Solutions

1948 ◽  
Vol 1 (3) ◽  
pp. 319
Author(s):  
AR Miller
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
High Polymer ◽  
Chain Molecules ◽  
Number Of Components ◽  
Ring Molecules ◽  
Closed Ring ◽  
Simple Chain ◽  
Branched Chain ◽  
Polymer Species

The configurational partition function for random mixtures containing any numbers of components which can consist of simple, simple chain, branched chain, or closed ring molecules is examined. Using a general statistical method a set of partial differential equations is obtained for the appropriate combinatory factor. The integrability of this set of equations is examined. This provides a criterion by which it can be decided in what cases a mathematically precise value for the combinatory factor can be obtained rigorously by solving the set of partial differential equations. In these cases general formulae are given for the combinatory factor. It is shown that precise formulae can be deduced rigorously (a) for all binary mixtures whether the components consist of simple, simple chain, branched chain, or closed ring molecules ; (b) mixtures of any number of components containing not more than one high polymer species, which can consist of closed ring equally well as of simple chain or branched chain molecules ; and (c) mixtures of any number of components containing more than one high polymer species provided these consist only of simple chain or branched chain molecules. It is also shown that even in the case in which the condition of integrability is not satisfied, an approximation, which involves negligible error for high polymer molecules, indicates that the general formula must still provide a good approximation practically. The approximations inherent in the physical model are also considered.

Molecular dynamics study on the phase diagrams of linear and branched chain molecules

2008 ◽  
Vol 344 (1-2) ◽  
pp. 52-60 ◽  
Author(s):  
Wen-Ze Ouyang ◽  
Zhong-Yuan Lu ◽  
Zhao-Yan Sun ◽  
Li-Jia An
Keyword(s):  
Molecular Dynamics ◽  
Phase Diagrams ◽  
Chain Molecules ◽  
Branched Chain

INFLUENCE OF IN SITU TWO-PHASE POLYMERS ON AGGREGATE STABILIZATION IN VARIOUS TEXTURED NORTH DAKOTA SOILS

1987 ◽  
Vol 67 (1) ◽  
pp. 209-213
Author(s):  
J. L. RICHARDSON ◽  
W. T. GUNNERSON ◽  
J. F. GILES
Keyword(s):  
Molecular Weight ◽  
Polyvinyl Alcohol ◽  
Polymerization Reaction ◽  
Two Phase ◽  
Chain Molecules ◽  
Clay Particles ◽  
Condensation Polymers ◽  
Branched Chain ◽  
Ether Alcohol

Two-phase in situ condensation polymers formed from amine and aldehyde monomers were tested on three differing soil textures for aggregating effectiveness and were compared to polyvinyl alcohol treated soils. The amine and aldehyde monomers differed in functionality (number of amines or carbonyl groups participating in the cross-linking polymerization reaction), molecular structure (branched versus straight chains and the number of polar structural groups) and molecular weight. Straight-chained molecules were more effective in aggregating soil than branched-chain molecules if a certain critical molecular weight was exceeded. The branched-chained and lower molecular weight molecules were less plastic. The number of polar monomer structural groups, notably ether, alcohol and amide oxygen, capable of bonding to clay particles determined aggregation effectiveness. PVA was effective at 0.1% concentration; two-phase polymers with long straight chains were effective at 5.0% by weight. Key words: Microaggregates, macroaggregates, amine, aldehyde, polyvinyl alcohol

Rates of conformational transitions in branched chain molecules

1981 ◽  
Vol 14 (2) ◽  
pp. 292-299 ◽  
Author(s):  
Jeffrey Skolnick ◽  
Wayne L. Mattice
Keyword(s):  
Conformational Transitions ◽  
Chain Molecules ◽  
Branched Chain

scholarly journals Thermal resistance effect on anomalous diffusion of molecules under confinement

2021 ◽  
Vol 118 (21) ◽  
pp. e2102097118
Author(s):  
Jiamin Yuan ◽  
Zhiqiang Liu ◽  
Yimo Wu ◽  
Jingfeng Han ◽  
Xiaomin Tang ◽  
...  
Keyword(s):  
High Temperature ◽  
Thermal Resistance ◽  
Anomalous Diffusion ◽  
Linear Chain ◽  
Column Experiments ◽  
Diffusion Resistance ◽  
Confined Systems ◽  
Chain Molecules ◽  
Branched Chain ◽  
Long Chain

Diffusion is generally faster at higher temperatures. Here, a counterintuitive behavior is observed in that the movement of long-chain molecules slows as the temperature increases under confinement. This report confirms that this anomalous diffusion is caused by the “thermal resistance effect,” in which the diffusion resistance of linear-chain molecules is equivalent to that with branched-chain configurations at high temperature. It then restrains the molecular transportation in the nanoscale channels, as further confirmed by zero length column experiments. This work enriches our understanding of the anomalous diffusion family and provides fundamental insights into the mechanism inside confined systems.

On the Degradation of Branched Chain Molecules

1956 ◽  
Vol 24 (4) ◽  
pp. 796-802 ◽  
Author(s):  
Robert Simha
Keyword(s):  
Chain Molecules ◽  
Branched Chain

Thermodynamic calculations of linear chain molecules using a SAFT model

2001 ◽  
Vol 99 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Yiping Tang, Zhaohui Wang, Benjamin C.-Y.
Keyword(s):  
Linear Chain ◽  
Thermodynamic Calculations ◽  
Chain Molecules
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