Development of environmentally friendly bio-epoxy coatings for water-repellent applications

Hydrophobic coatings are made of materials that have low affinity to water.Driven by their water-repellent properties, hydrophobic coatings are envisioned to be employed as antiicing and anti-corrosion coatings.Epoxy coatings, one of the most important thermosets, are commonly hydrophilic, and, therefore, preparing hydrophobic films from hydrophilic epoxy resins is a scientific challenge.Despite of the great achievements in preparing hydrophobic epoxy films with good performance, the preparation of hydrophobic epoxy coatings still faces two serious problems.First, the epoxy resins commonly used are derived from Bisphenol A, which is an organic compound produced from petroleum sources and has been found to be an endocrine disrupting chemical.Second, the synthesis procedures involve the use organic solvents or small organic compounds that are released into the air.In other words, current hydrophobic epoxy coatings are not environmentally friendly synthesized.Therefore, the ultimate aim of this research is to prepare hydrophobic coatings with epoxy resins obtained from biomass precursors without requiring the use of organic solvents during the film preparation.The developed bio-based coatings are examined for the antiicing and anti-corrosion performances.Three different epoxy polymer formulations were developed based on isosorbide, cardanol and glycerol.The bio-based contents of the polymer formulations were progressively increased by incorporating bio-based curing agents and hydrophobizers.Furthermore, the hydrophobization of the bio-based epoxy polymers was achieved to different degrees by the incorporation of various hydrophobizers.In addition, the wettability, thermal and mechanical properties of the bio-based thermosets were studied.The anti-icing and anti-corrosion performances of the epoxy coatings were also evaluated in relation with the bulk and surface properties of the coatings.The overall results of this research have demonstrated that coatings with hydrophobic coatings for water-repellent applications can be prepared from bio-based compounds with tunable properties according to the selected compounds and employed synthesis method.Therefore, this research contributes to the development of green epoxy coatings for water-repellent Abstract ii applications.Finally, future work is suggested for the continuation and enrichment of this research. Lay Summary iii Lay SummaryCoatings with the ability to repel water are called hydrophobic coatings.Because of this property, hydrophobic coatings can serve as protective coatings against corrosion since water provokes the corrosion of metals.Similarly, hydrophobic coatings can also function as anti-icing coatings that prevent the formation or reduce the adhesion of ice on surfaces.Using epoxy coatings, one of the most important industrial polymer coatings, for anti-icing and anti-corrosion applications is not the best option due to their hydrophilic nature.However, considerable research has successfully been done in the preparation of new hydrophobic epoxy coatings.Although there are various reports on the preparation of epoxy films with hydrophobic properties and good performances, the elaboration of hydrophobic epoxy coatings still presents two environmental concerns.First, the raw material from which epoxy resins are commonly prepared, Bisphenol A, is a compound obtained from petroleum sources and it has been identified as a toxic chemical to human health.Second, organic solvents are generally employed in the synthesis which are naturally evaporated during the coating preparation process and, therefore, contributing to the pollution of the air.In summary, current hydrophobic epoxy coatings are based on nonrenewable and toxic materials, and the process may cause environmental pollution.The objective of this research is, therefore, to solve the above two problems of the epoxy technology by preparing new hydrophobic epoxy coatings obtained from renewable materials or biomass without the use of toxic organic solvents.Three different epoxy coatings were developed from three different bio-based precursors: isosorbide, cardanol and glycerol.The wettability, thermal and mechanical properties of the bio-based thermosets were studied as well as their anti-icing and anti-corrosion performances.The overall results of this research have proven that biomass compounds are competitive candidates for the preparation of epoxy coatings with hydrophobic coatings for waterrepellent applications.Therefore, this research contributes to the progress of green hydrophobic epoxy coatings for water-repellent applications.Finally, some suggestion are given for the continuation of this research. Unravel the curing reaction mechanisms, thermal and mechanical properties, as well as the anti-icing and anti-corrosion performance of the bio-based coatings. Dissertation OverviewChapter 1 outlines the targeted problem of the research as well as its goals and findings.Chapter 2 provides a broader context on the problem addressed and its related topics useful in this research.Chapter 3 discusses the general characteristics of the methodology employed and the theory behind the characterization techniques used in this research.Chapter 4 presents the results and discussion on the synthesis of isosorbide-based coatings.Chapter 5 shows the results and discussion on the development of cardanol-based coatings.Chapter 6 provides the results and discussion on the fabrication of glycerol-based coatings.