All ETDs from UAB

Advisory Committee Chair

Selvum Pillay

Advisory Committee Members

Margaret Burnham

Katelyn Crawford

Su Gupta

Haibin Ning

Daneesh Simien

Document Type

Dissertation

Date of Award

2018

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

Cellulose nitrate lacquer is a coating system that is used in the conservation of silver art pieces in museums. This coating degrades prematurely in the presence of extensive light exposure, which is prominent in display cases, thus comprising the surface of the art piece. When facing this fact, it is imperative to create a new polymer coating system with an in-crease in barrier properties so that the life expectancy of the coating increases. The synthesis of a cellulose nitrate-layered silicate nanocomposite coating stands to enhance the barrier properties of cellulose nitrate through proper dispersion of layered silicates. A proper formulation procedure was created to ensure dispersion of the layered silicates. The formulation procedure included the use of an organically modified layered silicate (Cloisite 30B), solution intercalation, ultrasonication mixing, and high shear mixing. Before employing the nanocomposite films, the coating properties must be assessed and compared. UV-Vis analysis was used to measure the optical quality of the nanocomposite films in which they rival the optical quality of neat cellulose nitrate. Using a drying study on the rheometer, it was determined that the incorporation of layered silicates into cellulose nitrate decreased the drying time. A spraying study determined the incorporation of layered silicates into cellulose nitrate does not hinder the application process. Lastly, nanoindentation was used to measure the scratch resistance. It was determined that above 0.5wt% loading concentration of layered silicates, the coating becomes too brittle and more prone to debonding in the presence of a force. The desire for an increase in barrier properties is to enhance the UV stability of cellulose nitrate. The UV stability was measured using spectral reflectometry in which all film types displayed a 10% reflectance in the visible light spectrum after 36 hours of UV exposure. The thermal stability of the film was measured using DSC in which, after 36 hours of UV exposure, the 5wt% film displayed an endothermic peak at the highest temperature. The Kissinger equation was used to determine the rate of degradation. Estimating the activation energies showed that the 5wt% film was the least degraded after 36 hours of UV exposure.

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Engineering Commons

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