Date of Award

12-2004

Degree Name

Doctor of Philosophy

Department

Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. Margaret K. Joyce

Second Advisor

Dr. Paul D. Fleming

Third Advisor

Dr. Abhay Sharma

Fourth Advisor

Dr. Molly Williams

Abstract

Although additives are used in small amounts (below 2wt.% of the total solids) in a coating formulation, they play an important role in the runnability and end-use performance of the coating. Among coating additives, the use of insolubilizers and fluorescent whitening agents (FWA's) has increased due to theincrease in demand for higher quality graphic papers and packaging. Zirconium containing insolubilizers were studied for their rheological effects on silica ink jet coatings. Both zirconium species had an influence on the theological properties of the coating and its components. The interactions between thezirconium salts and the coating were found to be weak and lessened as the shear rate increased. In addition, fluorescent whitening agents were investigated for their optical effects. Studies in FWA's included a thorough evaluation of optical measurement techniques and whiteness formulas, instrument type, illumination conditions and paper grade effects on the optical measurements. The results showed several deficiencies in the current measurement techniques for assessment of brightness and whiteness of different grade papers and coatings containing FWA's and dyes. Most whiteness formulae used today assess a sample relatively as to whiter, lighter and bluer. The results showed that when these formulas are applied to colored samples they are generally unsuccessful in assessing tinted samples with chromaticities placed on the borders of white colors. New formulas expressing whiteness are proposed. These are compared with CIE (Commission Internationale de l'Eclairage), Hunter and Ganz whiteness formulas and TAPPI brightness through perceptual evaluation and instrumental measurements and analyses. Proposed formulas matched better with randomly selected observer assessments than the CIE, Hunter and Ganz whiteness formulas.

Access Setting

Dissertation-Open Access

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