Modified water diffusion kinetics in an unidirectional glass/fibre composite due to the interphase area: Experimental, analytical and numerical approach

This paper deals with the study of water diffusion in unidirectional composite associating experimental data, analytical and numerical models. A fibre/matrix interphase with a gradient of molecular mobility is characterized by microthermal analysis. The fibre dispersion observed by optical microscopy shows an important heterogeneity and many contacts between fibres. This particular fibre distribution as well as the interphase thickness have been considered to model our composite microstructure accurately. Diffusion kinetic parameters from water absorption measurements on both the resin and the UD composite were then used in the finite element analysis of the composite. The comparison between experimental data, analytical and numerical models show the influence of fibre distribution and interphase properties on water diffusion kinetic. An average water diffusion coefficient is then identified for the interphase.