Water vapour permeability, diffusion and solubility in latex films

Abstract

Water vapour diffusion D, solubility S and permeability P coefficients have been determined for films obtained from carboxylated styrene-butadiene (SB) copolymer latexes. The experimental method is water vapour sorption performed in the range 30-60°C. Using the small angle neutron scattering (SANS) method and a selective labelling with D,O vapour, it has been shown that water molecules mainly diffuse in the films through the particle-particle interfaces, which consist of a polar carboxyl-rich copolymer. It has been shown that the degree of cross-linking of the particles does not significantly affect the values of D and S. Moreover, the effect of neutralization conditions, regarding both the pH value of the initial latex and the nature of the neutralizing agent, has also been investigated. It has been found that D does not depend on these parameters, whereas S appears to be very sensitive to them. The results have been interpreted on the basis of the structural modifications of the films induced by neutralization. Finally, the hydrophilicity (or hydrophobicity) of the neutralizing agent has been identified as one of the key features for controlling the affinity ofthe latex film for water vapour and hence its permeability properties.

Ripening of cellular latex films

“…f Particle diameters according to pictures from transmission electron microscopy. 8 Fraction of crosslinked polymer in the core.…”

Film formation from monodisperse acrylic latices

“…Subsequently, L 1 , L 2 , and L 3 , are calculated with the aid of Eqs. (5). If the relative refractive index, m, is known, the polarizability α can be calculated with the aid of Eq.…”

“…The drying temperature has a major effect on film properties such as permeability [1][2][3][4][5] and redispersability [6,7]. In addition to the drying temperature, the relative humidity and the drying time also affect film properties.…”

Moisture transport in coated wood. Part 2: Influence of coating type, film thickness, wood species, temperature and moisture gradient on kinetics of sorption and dimensional change

“…Mantanis (1994) mentioned activation energies in the range of 32.2 to 50.2 kJ mol )1 for diffusion in uncoated wood. Richard et al (1993) reported activation energies of 35.2 kJ mol )1 for diffusion of water vapour into carboxylated styrenebutadiene copolymer latexes.…”