Predicting drying in coatings that react and gel: Drying regime maps

Cairncross, Richard A.; Francis, Lorraine F.; Scriven, L. E.

doi:10.1002/aic.690420107

Cited by 55 publications

(49 citation statements)

References 23 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, a glassy skin can form at the exposed surface. Since the molecular diffusion coefficient is smaller in the glassy region [1], [2], [3], the formation of such a skin slows desorption [7]. In extreme cases, trapping skinning can occur, and an increase in the driving force will decrease the total flux through the exposed surface.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Skinning During Desorption of Polymers: An Asymptotic Analysis

Edwards¹

1998

SIAM J. Appl. Math.

View full text Add to dashboard Cite

Abstract. Desorption of saturated polymers can be inhibited if a nearly dry (glassy) skin with a low diffusion coefficient forms at the exposed surface. In addition, trapping skinning can occur, where an increase in the force driving the desorption decreases the accumulated flux desorbed. The dynamics of such systems cannot be described by the simple Fickian diffusion equation. The mathematical model presented is a moving boundary-value problem with a set of two coupled partial differential equations. Most previous studies of this model focused on sorption studies; this is the first that considers desorption into an environment of arbitrary concentration. Since the derived equations cannot be solved by similarity variables, integral equation techniques are used to obtain asymptotic estimates for the solution. The skinning solution obtained also exhibits fronts moving with constant speed, another distinctive feature of non-Fickian polymer-penetrant systems.

show abstract

Section: Discussionmentioning

confidence: 99%

“…In extreme cases, trapping skinning can occur, and an increase in the driving force will decrease the total flux through the exposed surface. The lower diffusion coefficient in the glassy skin is not adequate to describe such behavior; rather, nonlinear viscoelastic effects must also be considered [2], [3], [10].…”

Section: Discussionmentioning

confidence: 99%

Skinning During Desorption of Polymers: An Asymptotic Analysis

Edwards¹

1998

SIAM J. Appl. Math.

View full text Add to dashboard Cite

show abstract

“…Although the behavior of amorphous polymers under various drying conditions has been studied, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] the drying characteristics of semicrystalline polymers are still lacking and are different from those of amorphous polymers. The removal of solvents from semicrystalline polymers opens a path for crystallization to occur because of voids during the drying process.…”

Section: Introductionmentioning

confidence: 99%

Understanding the effect of skin formation on the removal of solvents from semicrystalline polymers

Wong

Altınkaya

Mallapragada

2005

J Polym Sci B Polym Phys

View full text Add to dashboard Cite

The effect of glassy skin formation on the drying of semicrystalline polymers was investigated with a comprehensive mathematical model developed for multicomponent systems. Polymers with high glass-transition temperatures can become rubbery at room temperature under the influence of solvents. As the solvents are removed from the polymer, a glassy skin can form and continue to develop. The model takes into account the effects of diffusion-induced polymer crystallization as well as glassy-rubbery transitions on the overall solvent content and polymer crystallinity. A Vrentas-Duda free-volume-based diffusion scheme and crystallization kinetics were used in our model. The polymer-solvent system chosen was a poly(vinyl alcohol) (PVA)-water-methanol system. The drying kinetics of PVA films were obtained by gravimetric methods with swollen films with known water/methanol concentrations. The overall drying behaviors of the polymer system determined by our model and experimental methods were compared and found to match well.

show abstract

“…This phenomenon, called literal skinning [5][6][7], has many industrial applications. When drying wood, foods, or other agricultural products, the skinning behavior is manifested as "case hardening" [8][9][10], which can lead to residual stresses that can cause buckling and warping.…”

Section: Introductionmentioning

confidence: 99%

A Spatially Nonlocal Model for Polymer Desorption

Edwards

2005

J Eng Math

View full text Add to dashboard Cite

Abstract. In order to describe diffusion of a penetrant in a polymer entanglement network, one must incorporate nonlocal effects. Most previous models have included nonlocality in time only; however, by exploiting the disparate length scales in such systems, one can model these effects by a partial integrodifferential equation which is nonlocal in space. When considering the case of diffusion near the glass-rubber transition, a moving boundary separates the polymer into two regions, each governed by a different set of PDEs. The desorption of a semi-infinite polymer is studied using singular perturbation methods. Layers arise at the exposed surface, at the moving boundary, and initially. Analytical and phase-plane solutions are obtained for the solution, which exhibits physically realistic forms of desorption overshoot. Thus, spatially nonlocal models have the potential to replicate experimental systems, and should be considered in concert with other viscoelastic models of polymer-penetrant systems.

show abstract

Predicting drying in coatings that react and gel: Drying regime maps

Abstract: The competition between drying and reactions in a liquid

Cited by 55 publications

References 23 publications

Skinning During Desorption of Polymers: An Asymptotic Analysis

Skinning During Desorption of Polymers: An Asymptotic Analysis

Understanding the effect of skin formation on the removal of solvents from semicrystalline polymers

A Spatially Nonlocal Model for Polymer Desorption

Contact Info

Product

Resources

About