Ran Wei Rioux

Date of Award

5-2003

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Advisor

Douglas W. Bousfield

Second Committee Member

Yang Xiang

Third Committee Member

Adriaan R.P. van Heiningen

Abstract

Fluid flow in porous media is an important process for many applications such as oil recovery, packed bed absorption colun~ns and filtration. Short time fluid uptake is important for processes such as textile sizing, paper coating and printing. But more work is needed to characterize the parameters that determine the absorption rate. This work is focused on short time absorption rate on uncoated and coated paper. Absorption rate is measured with a Bristow Wheel device for seven different uncoated papers and eleven coated papers. Gloss dynamics of freshly printed samples and tack dynamics are measured with two novel devices. Various absorption models are compared to the experimental results. For absorption into paper, the absorption rate is found to be related to fluid-substrate contact angle and fluid properties. The combined influence of fluid viscosity, surface tension and contact angle on absorption rate is not well described by the Lucas-Washburn equation. For coated paper, the absorption rate depends on the base paper absorption rate, the coating pore size, coating binder level and fluid-coating contact angle. The coatings on high absorbance base paper have a higher absorption rate than coatings on low absorbance base paper. Small pore size of coating and low fluid-coating contact angle increase penetration rate. Low binder level in coating increases absorption rate. The absorption rate is proportional to the value of (γcos(θ)/ μ)0.5 as predicted by the Lucas- Washburn equation. Both the micro-tack and dynanlic gloss tests depend on absorption rate. A good relationship between the absorption rate and tack peak time is obtained. The dynamic gloss heel time correlates to absorption rate. The proposed model for absorption into paper works well, but the Lucas-Washburn expression over predicts the results. For coated samples, a model is proposed that predicts the results for inks and ethylene glycol, but the Darcy coefficient needs to be obtained from an absorption experiment. The Lucas-Washburn equation does not apply for coated paper absorption prediction.

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