In addition,there is vivid effect of swelling due to the regaining of the particle original shape,particle straightening.
Regaining the original shape and straightening of particles in the presence of water/vapour can cause the breakage of the glue bond hence swelling occurs
Halligan
According to Medved et al the interaction between moisture and the particleboard leads to the development of swelling stresses that cause the failure of the resin bond and the dislocation of the particles within the panel.