My oil/acrylic drying ideas.
For oil paint:
Linseed oil -> Oxidation -> Hydroperoxide lipid -> Decomposition ->Polymer stage + volatile product -> Hydrolysis -> liquid product + free fatty acids -> reaction with Zinc white or other soluble metal ions -> lithification (brittle but stable ionomeric product formation) + free soap formation -> free soap and fatty acids efflorescence on the surface + cracked lithificated ionomeric substance.
for acrylic:
Acrylic dispersion -> water evaporation -> surfactant migration on the surface or between layers -> acrylic globules bonding with each other (coalescense) -> film formation -> film shrinkage.