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Author ORCID Identifier

https://orcid.org/0000-0002-3762-7056

AccessType

Campus-Only Access for One (1) Year

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Chemical Engineering

Year Degree Awarded

2022

Month Degree Awarded

February

First Advisor

Jessica Schiffman

Second Advisor

John Klier

Subject Categories

Polymer and Organic Materials | Polymer Science

Abstract

Waterborne coatings and powder coatings are fast-growing sectors of the world coating market due to their environmentally friendliness as they have low or zero volatile organic compounds (VOCs) emission. However, compared with solventborne coatings, significant limitations need to be overcome to enable their broad applications. My dissertation will discuss several novel crosslinking strategies for waterborne and powder coating that could enable curing on-demand at ambient conditions, with facile polymerization and easy processing, and ultimately, exhibit a high degree of crosslinking and excellent performance that is comparable to solventborne coatings.

We introduced and demonstrated the anionic polymerization mechanism and the high reactivity of the novel monomer diethyl methylene malonate (DEMM). The direct emulsion polymerization of DEMM initiation by water at various pH values and functional groups was evaluated. Furthermore, (DEMM)6 was incorporated into the latex containing carboxyl acid as the functional group to provide a facile crosslinking methodology in improving coating performance. A second monomer hydroxyethyl methacrylate methylene malonate (HEMA-MM) was introduced to provide a simple post-functionalization approach by first grafting on latex particles via anionic polymerization, leaving the pendent HEMA groups for the subsequent free radical crosslinking of coating films upon UV exposure.

Next, we synthesized novel reactive microparticles to address the limitations of high-temperature baking required for traditional powder coatings. The particles were designed to have core-shell structures, comprised of a soft-core of thermoset resin bisphenol A diglycidyl ether modified with poly(butyl acrylate) and a protective polyurea shell. The effect of various core chemistries and viscosities on the deposition efficiency and the critical impact velocity were explored. We determined that particles that had a liquid core of epoxy resin yielded a dramatic improvement in both film formation and deposition efficiency up to 56%. Our work represents a significant breakthrough towards achieving reliable, efficient cold spray coatings at room temperature.

All in all, the dissertation investigated three crosslinking strategies for the formation of high-performance waterborne and powder coatings that meet the sustainability requirement with low VOCs, enable room temperature curing which lifts the restriction for both indoor and outdoor applications, and ultimately results in thermoset coating films with superior performance.

DOI

https://doi.org/10.7275/27373552

Available for download on Wednesday, February 01, 2023

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