Date of Award

Fall 12-15-2023

Level of Access Assigned by Author

Open-Access Thesis

Language

English

Degree Name

Master of Science (MS)

Department

Chemistry

Advisor

William M. Gramlich

Second Committee Member

Douglas W. Bousfield

Third Committee Member

Matthew Brichacek

Abstract

Water-borne barrier dispersion coatings on paper have emerged as an alternative to extrusion coatings on paper due to improved recycling, high application speed, and other end of life attributes. Pigments are often added to improve the performance of dispersion coatings. The use of pigments to form a Pickering emulsion during the polymerization step for the production of a barrier coating on paper has not been discussed in the literature.

In this study, montmorillonite (MMT) pigment varied from 0-6 % pigment volume concentration (PVC) was used to synthesize dispersion coatings consisting of poly(styrene-co-butylacrylate) latex and compared with sodium dodecyl sulfate surfactant for emulsion stability. The latex size, stability, and degree of conversion were obtained. The effect of these systems on water vapor transmission rate and water absorption of the films was compared. Additionally, characterization of the dispersion coatings and the coated paper substrate was conducted to understand the observed trend in the measured barrier properties.

The Pickering coating system decreased the water vapor transmission rate (WVTR) reaching a minimum at 1.2 % PVC compared to the surfactant coating that reached a minimum at 2 % PVC. At higher PVC, the WVTR of both systems increased. A similar trend was observed in the water absorption in the film of the latexes. The hydrophilicity of the MMT pigment, concentration of dispersant as well as penetration of the latex into the base paper were found to be the contributing factors for the observed low barrier properties. Moreover, similar pore volumes were found in all the latex film. Therefore, the decrease in barrier properties as PVC increased was not caused by pore generation. Addition of pigments to the latex could be considered beneficial to improving barrier properties up to a certain level beyond which the pigments form percolation networks along the interfaces between MMT and the polymer.

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