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The WLF equation is a consequence of time–temperature superposition (TTSP), which mathematically is an application of Boltzmann's superposition principle. It is TTSP, not WLF, that allows the assembly of a compliance master curve that spans more time, or frequency, than afforded by the time available for experimentation or the frequency range ...
An alternative model suggested by Arrhenius is also used. The WLF model is related to macroscopic motion of the bulk material, while the Arrhenius model considers local motion of polymer chains. Some materials, polymers in particular, show a strong dependence of viscoelastic properties on the temperature at which they are measured.
FENE-P is one of few polymer models that can be used in computational fluid dynamics simulations since it removes the need of statistical averaging at each grid point at any instant in time. It is demonstrated to be able to capture some of the most important polymeric flow behaviors such as polymer turbulence drag reduction and shear thinning.
Flory–Huggins solution theory is a lattice model of the thermodynamics of polymer solutions which takes account of the great dissimilarity in molecular sizes in adapting the usual expression for the entropy of mixing. The result is an equation for the Gibbs free energy change for mixing a polymer with a solvent. Although it makes simplifying ...
The second form of the equation is valid at steady-state polymerization, as the chains are being initiated at the same rate they are being terminated (R i = R t). [5] An exception is the class of living polymerizations, in which propagation is much slower than initiation, and chain termination does not occur until a quenching agent is added. In ...
The excluded volume of a hard sphere is eight times its volume—however, for a two-molecule system, this volume is distributed among the two particles, giving the conventional result of four times the volume; [2] this is an important quantity in the Van der Waals equation of state. The calculation of the excluded volume for particles with non ...
The newly formed nucleophile will then attack the atom X in another monomer molecule, and the sequence would repeat until the polymer is formed. [21] Anionic ring-opening polymerizations (AROP) involve nucleophilic reagents as initiators. Monomers with a three-member ring structure - such as epoxides, aziridines, and episulfides - undergo ...
The Vogel–Fulcher–Tammann equation, also known as Vogel–Fulcher–Tammann–Hesse equation or Vogel–Fulcher equation (abbreviated: VFT equation), is used to describe the viscosity of liquids as a function of temperature, and especially its strongly temperature dependent variation in the supercooled regime, upon approaching the glass transition.