What is Flory radius?
What is Flory radius?
(The direction of each step is random.) The Flory radius, RF, is defined by the random walk law, The Flory radius applies, for the most part, in the melt. When a polymer is put in solution with an organic solvent, such as polystyrene in gasoline, the coil expands to a larger size than the size reflected by equation 3.
What is the Flory Huggins parameter?
Abstract: The Flory–Huggins χ parameter describes the excess free energy of mixing and governs phase behavior for polymer blends and block copolymers. For chemically-distinct nonpolar polymers, the value of χ is dominated by the mismatch in cohesive energy densities of the monomers.
What are the assumptions made in Flory Huggins theory?
– mutual interaction energy between polymer and solvent molecules; R – universal gas constant; T – absolute temperature. A good plasticizer or solvent should have a low value.
What does the Flory Huggins interaction parameter signify?
For this reason, this parameter is often called Flory-Huggins Parameter. In early models and studies, the Flory-Huggins Parameter (χ) was assumed to be independent of concentration….Polymer-Solvent Interaction Parameter. at Infinite Dilution. (1)
| Polymer | Solvent | χ∞ |
|---|---|---|
| Poly(vinyl alcohol) | Water | 0.494 |
What is radius of gyration of polymer?
For a polymer chain, this is also the root-mean-square distance of the segments of the molecule from its center of mass. The radius of gyration is one measure of the size of the random coil shape which many synthetic polymers adopt in solution or in the amorphous bulk state.
What is K in Mark Houwink equation?
is intrinsic viscosity. K is a constant. With known values for and K it is easy to take the values from an intrinsic viscosity experiment and calculate .
Which is the formula for the radius of gyration?
The formula of moment inertia in terms of the radius of gyration is given as follows: I = mk2 (1) where I is the moment of inertia and m is the mass of the body. Accordingly, the radius of gyration is given as follows. (2) The unit of the radius of gyration is mm.
How is the Flory-Huggins Equation used in chemistry?
Flory-Huggins equation was used to estimate the monomer concentration in the amorphous region of the polymer. The time evolution of polymerization rate under all conditions followed the same pattern, with a fast decay in the early stage of the polymerization and a relatively slow decay in the later stage.
How is the Flory Huggins free energy density generalized?
The Flory-Huggins free energy density can be generalized to an N-component mixture of polymers with lengths As in the case for dilute polymer solutions, the first two terms on the right-hand side represent the entropy of mixing. For large polymers of
Which is an effect of Flory Huggins theory?
One well-studied effect on interaction energies neglected by unmodified Flory Huggins theory is chain correlation. In dilute polymer mixtures, where chains are well separated, intramolecular forces between monomers of the polymer chain dominate and drive demixing leading to regions where polymer concentration is high.