Effect of Varying Crosslinker for PMAA Hydrogel Particles on Swelling Properties and Water Management in Protective Coating Systems

摘要

Organic protective coatings remain the state of the art for corrosion prevention. These coatings must possess barrier properties sufficient to survive the challenges of the service environment, i.e., water, oxygen, and electrolyte permeation. Water and electrolyte diffusion to the coating-substrate interface not only propagates the corrosion reaction but decreases adhesion to the substrate. The control of water diffusion in a polymer matrix allows for an increased lifetime before corrosion initiation. This research focuses on the synthesis of a series of hydrogels, that vary in particle size and chemical composition through changing the crosslinker. These changes will result in understanding of water absorption properties and applied to model polymeric matrices to mitigate water diffusion to the coating-substrate interface. These systems will be comprised of poly(methacrylic acid) (PMAA) to be crosslinked by aliphatic and aromatic diamines and dimethacrylates. Varying the polarity of the hydrogel particle by changing the crosslinker is hypothesized to decrease particle diameter and water uptake with smaller molecular weight crosslinkers. Herein, chemical and physical properties of the hydrogel series are reported including T_g, swellability, and particle size. The particles will be incorporated into model thermoplastic and thermoset anti-corrosive coatings for characterization of corrosion control and diffusion properties. Understanding the tunability of hydrogel water uptake and particle size will allow for future studies with controlled transport properties of contaminants in a corrosion control coating.