Where θ is the slope, which can be calculated from the graph between the Qt and t1/2, and h is the initial thickness of the sample. The value of D has been given in Table V. It is clear from Table V that as the temperature increases, the diffusion coefficient increases. The diffusion coefficient characterizes the ability of the solvent to move along with the polymer segment. As the temperature increases, the activity within the polymer molecules enhances, which helps the water moleculesto diffuse in to the composites through the fillers and the voids present in it due to foaming. However, the trend of diffusion coefficient is not regular with increase in filler contents in composites.24,25 It is because the diffusion in wood polymer composites occurs through different mechanisms being the different natures of the polymer and wood filler. Hence, variation in diffusion is observed.