Date of Award
Summer 6-2023
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. Derrek L. Patton
Committee Member 2 School
Social Science and Global Studies
Committee Member 3
Dr. Xiaodan Gu
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. Jeffrey Wiggins
Committee Member 5 School
Polymer Science and Engineering
Abstract
Coatings mitigate corrosion on assets in varied environments by acting as barriers to aggressive molecules while maintaining adherence to the asset substrate. Eventually, the coatings will be breached or defects in the coatings will transition into breaches. Then, the performance of breached coatings no longer depends on film barrier properties, but on the lateral (x, y-axis) resistance to cathodic delamination as a new type of adherence strength at the polymer-substrate interface. The adherence strength in turn mitigates substrate dissolution (corrosion). Currently, the literature lacks a direct means to detect the earliest onset of coating failure using a nondestructive method and to identify and connect relevant polymer characteristics that mitigate the corrosion process at the polymer-substrate interface.
We employed confocal laser scanning microscopy and electrochemical frequency modulation to conduct quantifiable time-lapse acquisitions for corrosion mitigation performance of polymer systems applied to rolled steel panels while immersed in 5 wt% NaCl saline solution. CLSM was used to quantify the varying delay time for micro-blister initiation, the velocity of micro-blister growth from a defect, and the initiation of corrosion at the polymer-substrate interface in all locations relative to the defect. Increasing the hydrophilic content of the crosslinker decreased the delay time for the initiation of the micro-blister front propagation distally radially away from the defect from 47.5, 25.0, 21.0, and 5.5 hours, respectively. We hypothesize that attainment and maintainment of adherence and the micro-blister front propagation rates are dependent upon the mechanical property relationships of the polymer coating to manage environmental work done to the system during exposure. We were focused on the extent of swelling that governs how the bulk polymer functions as a top scaffolding over the substrate to resist deformation, micro-blister formation, and growth with respect to polymer-substrate interface corrosion.
Recommended Citation
Scanlon, Christopher, "Novel Corrosion Detection Methods for Understanding Polymer Model Coatings During Immersion" (2023). Dissertations. 2167.
https://aquila.usm.edu/dissertations/2167