An Investigation on the Capillary Wetting of Glass Fiber Tow and Fabric Structures with Nanoclay-Enriched Reactive Epoxy and Silicone Oil Mixtures
journal contributionposted on 26.08.2009, 00:00 authored by Ayça Ertekin, Sadhan C. Jana, Richard R. Thomas
Capillary wetting of a biaxially-oriented glass fabric and the tow comprising the fabric was examined via the Washburn equation with silicone oil and a reactive epoxy-curative system containing 0−4 wt % nanoclay reinforcement. Capillary wetting of silicone oil was used to measure the hydraulic constant of the fabric and tow. The wetting rates for fabric were found to be greater than those for tow and this was based on the larger pore radii of fabric compared to tow. Reynolds and capillary numbers calculated from wetting rate data indicated that the flow is dominated by interfacial tension. The presence of nanoclay offered a significant perturbation to capillary wetting behavior. Wetting rates indicate that the effect of nanoclay is 2-fold: blocking of tow pores and increasing the wetted area. This suggests that nanoclay particles are aggregating and the flow field is such that the particles are not dispersed additionally under the present conditions. Capillary wetting rates of fabric and tow samples were measured with reactive epoxy-amine mixtures at various nanoclay loadings. The presence of nanoclay offers another level of complexity to the Washburn equation. In addition to the liquid/fabric or tow interfacial tension, the interfacial tension of the liquid/nanoclay interface has to be reconciled. As a consequence, hydraulic constant, surface tension, and contact angle are convoluted in such a binary system.