Seawater Absorption in Unidirectional Carbon/Vinylester

摘要

The objective of this work is to characterize the moisture transport in arnunidirectional carbon/vinylester composite. Specifically considered is moisturerntransport by diffusion through the matrix and gaps between fiber and matrix. Moisturerntransport along the fiber/matrix interface is known as “wicking”. This mechanism ofrnwater transport is accelerated if the ends of the fibers are exposed. The Fickian modelrnis applied to moisture diffusion. The transport of moisture due to wicking is modeledrnusing Darcy’s law.rnThe Fickian diffusion model predicts an initially linear increase in moisturerncontent vs. square root of time with saturation approached asymptotically. Therncapillary model predicts a linear increase in moisture content vs. time up to saturationrnof the capillaries. A small unidirectional carbon/vinylester 510A panel and a neat resinrnvinylester 510A panel were immersed in seawater at 40℃. The moisture content wasrnmonitored until saturation. The times for saturation of moisture content for compositernspecimen as predicted by the diffusion and capillary flow models are of similar orderrn(36 and 27 days), while the actual panels reached saturation much faster (about 15rndays). The capillary model assumes that the capillaries are circular extending throughrnthe length of the composite. In reality, the capillaries are likely to have a different andrnvariable shape along the fiber/matrix interface.