Originating from plants as a natural, renewable resource, paper-based materials have garnered significant interest in recent years across packaging and non-packaging sectors. However, the utility of paper-based packaging remains limited due to its porous nature and the presence of hydroxyl (-OH) groups, which confer hydrophilic characteristics. This makes it susceptible to the permeation of liquids and gases through cellulose fibers, leading to rapid deterioration of its barrier and mechanical properties.To address these shortcomings and promote broader adoption of paper-based packaging in daily life, various coating materials have been developed and applied to paper surfaces. For instance, PFAS (per- and polyfluoroalkyl substances, also known as "forever chemicals") and synthetic polymers like polyethylene (PE) and polypropylene (PP) have been widely used. However, these fluorinated chemicals are toxic, and plastic-based packaging presents additional challenges, such as low recycling rates (currently <9% in the U.S.), extremely slow degradation rates (>100 years), and microplastic contamination of landfills and water bodies. This PhD thesis explores the potential of sustainable, plant-based soybean oil as a source for paper coatings, offering a greener alternative to develop recyclable, repulpable, and biodegradable paper packaging materials with enhanced water and oil resistance properties. The first section of the thesis highlights the use of acrylated epoxidized soybean oil (AESO) for paper coating applications. AESO coatings achieved exceptional oil and water resistance, as evidenced by a perfect kit rating (12/12) and a Cobb1800 value (~2 g/m2). The coating process involved applying AESO with 2 wt% of a photoinitiator (2-hydroxy-2-methylpropiophenone) using a doctor blade, followed by UV curing to form a highly crosslinked polymeric surface. Notably, this study is the first to demonstrate pure AESO's potential in paper coating with extended water resistance testing of 30 minutes, significantly surpassing the previous benchmark of 60 seconds. The second section focuses on optimizing a waterborne coating system using an AESO blend with biocompatible polyvinyl alcohol (PVOH) as an emulsifying agent. PVOH, approved for direct food contact, provides a sustainable approach to emulsifying AESO. The AESO emulsion was applied to kraft paper, UV-cured, and achieved excellent oil and water repellency, with Cobb600 and Cobb1800 values of ~9 and ~13 g/m2, respectively, and a kit rating of 7/12. Optimization of AESO loading revealed that the best-performing sample had a loading range of ~15–20 g/m2. The coated paper retained over 90% of its mechanical properties and demonstrated more than 90% biodegradation within 90 days under industrial conditions. The third section investigates the incorporation of magnesium hydroxide nanoparticles (Mg(OH)2 NPs) into the waterborne AESO system to impart antimicrobial properties for potential applications in food and medical packaging. The Mg(OH)2 dispersion in the AESO emulsion produced coatings with robust water and oil resistance. Tests revealed excellent moisture and oxygen barrier performance (in thin films of cured AESO) and a ~4 log reduction in E. coli populations, achieving 99.99% bacterial elimination. These properties make the coated paper highly suitable for food and medical packaging applications. The fourth section examines the integration of degradable crosslinkers into soybean oil to enhance the recyclability of coated paper. A photocurable AESO emulsion was blended with oligoacrylate lactide/glycolide to improve recyclability. In parallel, epoxidized soybean oil (ESO) was modified with glycolic and methacrylic groups. Hexagonal boron nitride (H-BN) nanosheets were employed as emulsifiers to stabilize these blends. The coated paper underwent extensive water and oil resistance tests, with its repulpability and recyclability successfully validated. Vermicomposting tests confirmed the compostability of the coated paper, presenting a sustainable alternative to conventional PFAS-coated packaging materials.
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