Sustainable Thermosetting Polymers: Biobased Epoxy Resin Systems and Aqueous Non-Isocyanate Polyurethanes

Abstract

In recent years, there has been a desire to seek alternatives to petrochemically derived materials. These alternatives can be derived from renewable sources such as vegetable oils. However, methods for achieving sustainability are not limited to only resourcing materials from bio-based sources but can also be achieved by utilizing safer synthesis techniques, reducing cure times, and eliminating volatile organic content in thermoset coating formulations. This dissertation sets out to achieve a goal the sustainability across different fields. Epoxidized sucrose soyate is a versatile bio-based materials that is typically synthesized utilizing hydrogen peroxide and acetic acid. A proposed safer alternative utilizes Oxone to generate dimethyldioxirane intermediates at room temperature to achieve the epoxidation of unsaturated sites in sucrose soyate and other vegetable oils such as soybean oil and hempseed oil. Thermosets made from epoxidized bio-based sources synthesized from dimethyldioxirane intermediates or in-situ generated peracids showed little to no difference in thermal and coatings properties. The use of epoxidized sucrose soyate with reactive diluents in cationic photopolymerization was also explored. The thermal characterizations of the thermoset coatings created utilizing this method indicate that crosslinking had not occurred to completion. In an effort to reduce the use of volatile organic content the feasibility of utilizing cyclic carbonates and primary carbamates in water borne polyurethane systems was explored. It was found that utilizing cyclic carbonates with higher ring strain, such as 6-membered cyclic carbonates, provides a potential way for creating non-isocyanate crosslinking thermoset coatings from waterborne polyurethane dispersions.