Structural analysis of pore size distribution of nonwovens†

Pore size distribution is a prerequisite to investigate any transport phenomena, especially in a porous structure such as nonwovens. The pores inside the nonwovens are highly complex in terms of the sizes, shapes and the capillary geometries. The majority of existing theories/models of pore size distribution of nonwovens do not account for the fibre orientation distribution characteristics. In this research work, the model for predicting the pore size distribution of nonwoven structures has been developed by combining the stochastic and stereological or geometrical probability approaches. These techniques have incorporated the effects of fibre orientation characteristics in nonwoven structures. The analytical model formulated is compared with the existing theories to predict the pore size distribution of nonwoven structures. A comparison is also made between the experimental and theoretical pore size distributions of spun-bonded and needle-punched nonwovens. The effect of various fibre and fabric parameters including fibre volume fraction, fibre orientation distribution characteristics and number of layers on pore size distribution of nonwoven structures has been investigated.