| Résumé : |
Waterborne organic coatings can be improved thanks to a better understanding of how small molecules affect their properties.
Waterborne coatings often contain small molecules (with low molecular weight as opposed to the macromolecules forming the matrix), wheter intentionally or not. These small molecules can be, for instance, undesirable residual monomers or oligomers; or they can be voluntary added formulation additives such as wetting agents, crosslinkers, adhesion promoters, plasticisers, coalescents, stabilisers or texturing agents. These molecules have a profound influence on properties. Not only do the small molecules affect properties through their total amount, but also, at a given concentration, through their distribution in the film. For example, if a small molecule, such as a surfactant, accumulates at the film-substrate interface of a water-borne coating, adhesion propertiesn especially in wet conditions, are strongly affected. Another example is food packaging and food can varnishes, where non-polymeric molecules should not migrate to the surface in contact with food. |
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A question of distribution in POLYMERS PAINT COLOUR JOURNAL - PPCJ, Vol. 192, N° 4448 (01/2002)
