Path tortuosity for permeant water molecules at the nanoscale can be increased by addition of nanoclay to the PA-6 phase, which has an affinity for water due to the formation of hydrogen bonds.
This approach would be particularly effective when the more permeable phase is dispersed, by isolating it from the permeant.
Gravimetric measurements were performed to determine how the shape and size of the permeant molecules would influence their diffusion behaviour into the polyester matrix and each permeant will be discussed separately.
Increase of the temperature lowers the amount of permeant required to achieve plasticization and increases the rate at which the chains can reorganise.
The steady-state regime is connected to a constant concentration of the permeant
As seen above, many applications of high technological impact depend on membranes and, therefore, the knowledge of the constituent polymeric materials is crucial, as well as the interactions between the permeant
molecules and the polymer molecules.
According to this reasoning, the permeation process is expected to be primarily dependent upon the amorphous volume of a polymer, available for migration of permeant
It is generally recognized that the molecular composition and structure in the amorphous phase of the polymer can greatly affect its barrier properties, since the permeant
molecules are believed to enter and diffuse through the polymer mostly by penetrating through its amorphous regions.
The dispersed clay platelets may strongly affect permeability by dictating a tortuous pathway for permeant
molecules transversing through the nanocomposite.
m] of the dispersed and matrix phases in the direction of permeant
One study (6), for example, found that more numerous and smaller PET spherulites allowed greater oxygen permeability than samples of equivalent crystallinity but larger size spherulites; that is, larger spherulites were more effective in creating increased tortuosity in the path of the oxygen permeant
Therefore, a mathematical model was developed to predict the number of layers needed to change permeant
flux by a certain amount for a variety of generalized conditions.
must dissolve into the barrier (the rate is governed by the solubility coefficient, S), diffuse through the barrier (governed by the diffusion constant, D) and emerge on the other side of the barrier.
The parallel coupling of components implies that all constituents (phases) are continuous in the direction of the permeant
flux [16, 24] (or acting force in the case of mechanical properties).
This reduction in Wc may significantly shorten the permeant
path of xylene molecules as Ccps increase and compromise the beneficial effect of "crosslinked" CP/PA molecules on the barrier properties of MPAs.