Date of Award

Winter 12-2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Dr. James W. Rawlins

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Dr. Sarah E. Morgan

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

Dr. Derek L. Patton

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Dr. Sergei I. Nazarenko

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Dr. Jason D. Azoulay

Committee Member 5 School

Polymer Science and Engineering

Abstract

Metallic corrosion has become an annual multibillion-dollar problem for the industrialized world and global contamination issue through the process of repair, removing, and reapplying protective coatings. Typical corrosion resistant coatings are comprised of polymeric coating layers with anti-corrosive pigments, plasticizers, sacrificial additives, and/or other formulation materials, which are formulated to prevent, detect, and manage corrosion. Our counterintuitive approach was to improve upon the understanding of how, when, where, and why environmental contaminants (reactants, mainly water and electrolytes) driving corrosion, propagate and accumulate as localized hydrophilicity shifts within a model polymer coated substrate. Herein, hydrogel particles (HGP) were synthesized of defines size and hydrophilicity, then blended into control model thermoplastic and thermoset polymer films at various loading levels, increasing overall thicknesses, and different distance from the metallic substrate interface.

Hydrogel-polymer blended films were analyzed in various ways to determine how water diffuses and traverses within the coatings and resulting physical properties based on loading level, defined HGP distance from the substrate-coating interfacial region (SPIR), polymer type, and polymer molecular weight to define the relationship between the HGPs and polymeric coating. The results from HGPs blended films consistently resulted in definitively higher equilibrium water uptake and yet 48% less water was measured at the SPIR. Water was quantified as being trapped and interacting directly and locally with the HGPs in blended films despite polymer type and chemistry. These films consistently exhibited increased modulus values after water saturation via RH-DMA at 90% RH highly dependent on the HGPs location but was highly dependent on HGP location and concentration. These results were believed to be driven by HGP swelling and expansion during hydration resulting in a consistent measurable increase in storage modulus. With a defined hydrophilic location, the high affinity for water driven by HGPs controlled water through thermodynamically favored domains that reduced corrosion and hydroplasticization effects whereby wet and dry adhesion were impacted positively in the presence of HGPs. Through this work, it was determined that water entrapment was possible with HGPs swelling within polymers forcing an increased modulus and maintain adhesion then corrosion was consistently less prevalent, and coatings performance was extended.

ORCID ID

0000-0002-5027-9471

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