The relationship between the equilibrium melting temperature and the supermolecular structure of several polyoxetanes and polyethylene oxide

1987 ◽  
Vol 27 (11) ◽  
pp. 781-787 ◽  
Author(s):  
C. J. Murphy ◽  
G. V. S. Henderson ◽  
E. A. Murphy ◽  
L. H. Sperling
Keyword(s):  
Melting Temperature ◽  
Polyethylene Oxide ◽  
Supermolecular Structure ◽  
Equilibrium Melting Temperature ◽  
The Relationship

scholarly journals Molecular Dynamics Study of Ion Transport in Polymer Electrolytes of All-Solid-State Li-Ion Batteries

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1012
Author(s):  
Takuya Mabuchi ◽  
Koki Nakajima ◽  
Takashi Tokumasu
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Ion Transport ◽  
Polyethylene Oxide ◽  
Polymer Electrolytes ◽  
Li Ion Batteries ◽  
Transport Mechanisms ◽  
Li Ion ◽  
Dynamics Simulations ◽  
The Relationship

Atomistic analysis of the ion transport in polymer electrolytes for all-solid-state Li-ion batteries was performed using molecular dynamics simulations to investigate the relationship between Li-ion transport and polymer morphology. Polyethylene oxide (PEO) and poly(diethylene oxide-alt-oxymethylene), P(2EO-MO), were used as the electrolyte materials, and the effects of salt concentrations and polymer types on the ion transport properties were explored. The size and number of LiTFSI clusters were found to increase with increasing salt concentrations, leading to a decrease in ion diffusivity at high salt concentrations. The Li-ion transport mechanisms were further analyzed by calculating the inter/intra-hopping rate and distance at various ion concentrations in PEO and P(2EO-MO) polymers. While the balance between the rate and distance of inter-hopping was comparable for both PEO and P(2EO-MO), the intra-hopping rate and distance were found to be higher in PEO than in P(2EO-MO), leading to a higher diffusivity in PEO. The results of this study provide insights into the correlation between the nanoscopic structures of ion solvation and the dynamics of Li-ion transport in polymer electrolytes.

Thermodynamics of Crystallization in High Polymers. Natural Rubber

1955 ◽  
Vol 28 (3) ◽  
pp. 718-727 ◽  
Author(s):  
Donald E. Roberts ◽  
Leo Mandelkern
Keyword(s):  
Natural Rubber ◽  
Melting Temperature ◽  
Low Temperatures ◽  
Rapid Heating ◽  
Heat Of Fusion ◽  
Low Molecular Weight ◽  
Heating Rates ◽  
Equilibrium Melting Temperature ◽  
Clapeyron Equation ◽  
Melting Temperatures

Abstract The existence of an equilibrium melting temperature, T0m, at 28 ± 1°, for unstretched natural rubber has been established, using dilatometric methods. The lower melting temperatures previously observed are a consequence of the low temperatures of crystallization and the rapid heating rates employed. From melting point studies of mixtures of the polymer with low molecular-weight diluents, the heat of fusion per repeating unit, ΔHu has been evaluated as 15.3 ± 0.5 cal./g. The values of ΔHu and T0m have then been combined with data of other workers to obtain the following information concerning natural rubber: (1) The variation of melting temperature with applied hydrostatic pressure has been calculated from the Clapeyron equation to be 0.0465° C/atm. (2) The degree of erystallinity resulting from maintaining a sample at 0° until the rate of crystallization is negligible has been calculated, by three independent methods, to be in the range 26 to 31 per cent. (3) Analysis of the stress-strain-temperature relationship has indicated that crystallization is the cause of the large internal energy changes that are observed at relatively high elongations.

Ammonia borane–polyethylene oxide composite materials for solid hydrogen storage

2015 ◽  
Vol 3 (7) ◽  
pp. 3683-3691 ◽  
Author(s):  
A. S. Nathanson ◽  
A. R. Ploszajski ◽  
M. Billing ◽  
J. P. Cook ◽  
D. W. K. Jenkins ◽  
...  
Keyword(s):  
Composite Materials ◽  
Hydrogen Storage ◽  
Melting Temperature ◽  
Polyethylene Oxide ◽  
Incubation Time ◽  
Ammonia Borane ◽  
Solid Hydrogen ◽  
Hydrogen Release ◽  
Crystal Phase ◽  
Oxide Composite

Co-electrospinning ammonia borane (AB) and polyethylene oxide (PEO) has created a unique crystal phase that promotes faster hydrogen release from AB below its melting temperature with no incubation time.

Pressure dependence of equilibrium melting temperature of poly (lactic acid)

Polymer ◽  
2017 ◽  
Vol 118 ◽  
pp. 297-304 ◽  
Author(s):  
David Rohindra ◽  
Keiichi Kuboyama ◽  
Toshiaki Ougizawa
Keyword(s):  
Lactic Acid ◽  
Melting Temperature ◽  
Pressure Dependence ◽  
Poly Lactic Acid ◽  
Equilibrium Melting Temperature

Size-dependent melting temperature of nanoparticles based on cohesive energy

2014 ◽  
Vol 28 (19) ◽  
pp. 1450157 ◽  
Author(s):  
Kai-Tuo Huo ◽  
Xiao-Ming Chen
Keyword(s):  
Melting Temperature ◽  
Cohesive Energy ◽  
Metallic Nanoparticles ◽  
Present Model ◽  
Packing Fraction ◽  
Size Dependent ◽  
Crystal Cell ◽  
K Factor ◽  
The Relationship ◽  
Crystalline Plane

Size-dependent melting temperature of metallic nanoparticles is studied theoretically based on cohesive energy. Three factors are introduced in the present model. The k factor, i.e. efficiency of space filling of crystal lattice is defined as the ratio between the volume of the atoms in a crystal cell and that of the crystal cell. The β factor is defined as the ratio between the cohesive energy of surface atom and interior atom of a crystal. The qs factor represents the packing fraction on a surface crystalline plane. Considering the β, qs and k factors, the relationship between melting temperature and nanoparticle size is discussed. The obtained model is compared with the reported experimental data and the other models.

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