Date of Award

Summer 8-6-2015

Level of Access

Campus-Only Thesis

Degree Name

Master of Science in Chemical Engineering (MSChE)

Department

Chemical Engineering

Advisor

William Gramlich

Second Committee Member

Douglas Bousfield

Third Committee Member

Paul Millard

Abstract

Binders like starch and latex are known to migrate relative to the pigment during coating and drying of paper. This migration influences important properties such as coating strength and printability. A better understanding of binder migration can help determine key parameters.

A technique to tag starch and latex with a fluorescent molecule was developed. Rhodamine B was used to tag latex. Fluorescein Isothiocyanate (FITC) was used for starch. A three dimensional analysis was obtained by using a confocal laser scanning microscope (CLSM) to image fluorescently active samples. A fluorescence microscope was also used to image cross sections of the samples. The tagged components were made into individual or mixed coatings and applied to various papers. Single layers, dual layers, and mixed coatings were applied using two different coating methods on six different paper substrates.

Attempts to stain samples after coating were not successful because the stains adsorb to both starch and latex to some degree; these results confirm the need to tag components before application. Starch was covalently bound to the FITC so that 35% of the total starch molecules were tagged with FITC. Latex was tagged with rhodamine B through rigorous mixing. Both the starch and latex showed large amounts of fluorescence for the level of addition reported. These tagged components can also be made into coatings that can be imaged successfully. Image analysis of coatings shows the distinct positions of both starch and latex. Cross section imaging shows a clear distinction between the starch and the latex when they are applied as separate layers. When they are mixed together, some regions near fiber surfaces are seen to be starch rich while other regions are still a mixture.

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