The 13th International Conference on Flow Processing in Composite Materials Experimental Investigation of Capillary Flow Porometry for Characterization of Dual Scale Porosity in Fibrous Reinforcements

Introduction Engineering textiles used in composite materials can be considered as porous materials because of the open spaces between the fibers in a bundle and between the woven bundles themselves. These spaces are commonly referred to as microscopic and mesoscopic pores. The dual scale porosity of fibrous reinforcements is of great importance when studying Liquid Composite Molding (LCM) processes because the pore size distribution directly influences the resin flow and fabric impregnation during the injection stage. For example, Vernet and Trochu [1] used optical microscopy to investigate experimentally the mesoscopic pore size distribution in 3D interlock fabrics in order to validate a predictive permeability model. Though theoretically possible, applying such an approach to characterize the microscopic pore size distribution would represent a daunting task. In contrast, capillary flow porometry is a relatively simple characterization technique widely used up to now to study simple scale porous media such as membranes, filtration media, paper, etc... [2, 3]. In the present study, this method will be applied in a novel way to characterize engineering textiles used in high performance composites. The main objective is to demonstrate its potential to quantify the dual scale pore size distribution of anisotropic fibrous reinforcements.