When n lies between 0.5 and 1, the diffusion isanomalous. This is the case when permeant mobilityand polymer segmental relaxation rates are almostequal. It is clear from Table IV that when the value of n approaches 0.5, the system obeys the Fickian behavior,i.e., the water absorption increases linearly with square root of time and then gradually approachesequilibrium.The diffusion coefficient (D) of the wood flourfoamed composites can be calculated from following equation23: