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Molecular Thermodynamic Model (molecular + thermodynamic_model)

Distribution by Scientific Domains
Polymers and Materials Science60%

Selected Abstracts

Molecular thermodynamic model of the glass transition temperature: dependence on molecular weight

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2008
Yong Woo Kim
Abstract A new molecular thermodynamic model to predict the dependency of the glass transition temperature (Tg) of polymer on its molecular weight was developed based on the configurational entropy model and the Flory,Huggins theory. In this model, the disorientation entropy of the polymer (Sdis) has been taken into account. Quantitative descriptions according to the proposed model are consistent with experimental Tg data of several polymers against the number of chain segment (r). At the same Tg., (Tg of polymer at a infinite r value), the degree of polymer disorientation is strongly correlated with the slope of straight line at lower r regions in the Tg versus r plot, which is quantitatively identified by physical parameter (,dis) in this model. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Molecular thermodynamic model for associated polymers,

CHINESE JOURNAL OF CHEMISTRY, Issue 12 2001
Chang-Jun Peng
Abstract A molecular thermodynamic model for homopolymer and copolymer systems with association segments was established by adopting the molecular thermodynamic model for hardsphere-chain fluid as a reference, a perturbation term contributed by the square-well potential and a contribution of association terms. The latter considers the multi-associated-segments in a chain-like molecule based on the shield-sticky model of chemical association. The model can be used to correlate the pVT of melten homopolymer and copolymer. Good agreements with experimental data have been obtained. [source]

Ionic conductivity of solid polymer electrolytes for dye-sensitized solar cells

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
Joo Wan Kim
Abstract We developed an ionic conductivity model of solid polymer electrolytes for dye-sensitized solar cells (DSSCs) based on the Nernst,Einstein equation in which the diffusion coefficient is derived from the molecular thermodynamic model. We introduced concentration-dependence of the diffusion coefficient into the model, and the diffusion coefficient was expressed by differentiating the chemical potential by concentration. The ionic conductivities of polymer electrolytes (PEO/LiI/I2 system) were investigated at various temperatures and compositions. We prepared a set of PEO in which an EO : LiI mole ratio of 10 : 1 was kept constant for PEO·LiI·(I2)n compositions with n = 0.02, 0.05, 0.1, 0.15, 0.2, and 0.3 (mole ratio of LiI : I2). The ionic conductivities of the electrolytes were measured using a stainless steel/polymer-electrolyte/stainless steel sandwich-type electrode structure using alternating current impedance analysis. The values calculated using the proposed model agree well with experimental data. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Molecular thermodynamic model of the glass transition temperature: dependence on molecular weight

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 8 2008
Yong Woo Kim
Abstract A new molecular thermodynamic model to predict the dependency of the glass transition temperature (Tg) of polymer on its molecular weight was developed based on the configurational entropy model and the Flory,Huggins theory. In this model, the disorientation entropy of the polymer (Sdis) has been taken into account. Quantitative descriptions according to the proposed model are consistent with experimental Tg data of several polymers against the number of chain segment (r). At the same Tg., (Tg of polymer at a infinite r value), the degree of polymer disorientation is strongly correlated with the slope of straight line at lower r regions in the Tg versus r plot, which is quantitatively identified by physical parameter (,dis) in this model. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Molecular thermodynamic model for associated polymers,

CHINESE JOURNAL OF CHEMISTRY, Issue 12 2001
Chang-Jun Peng
Abstract A molecular thermodynamic model for homopolymer and copolymer systems with association segments was established by adopting the molecular thermodynamic model for hardsphere-chain fluid as a reference, a perturbation term contributed by the square-well potential and a contribution of association terms. The latter considers the multi-associated-segments in a chain-like molecule based on the shield-sticky model of chemical association. The model can be used to correlate the pVT of melten homopolymer and copolymer. Good agreements with experimental data have been obtained. [source]