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Abstract
The demand for sustainable alternatives to petroleum-based coatings has driven interest in biodegradable polymers such as polyhydroxyalkanoates (PHA). However, challenges related to dispersion stability, coating flexibility, and adhesion have limited their widespread adoption. This dissertation investigates the formulation and optimization of PHA-based aqueous dispersions, emphasizing improved analytical methods and novel additives to enhance performance. The study first examines the role of surfactant selection and hydrophilic-lipophilic balance (HLB) values on dispersion stability and particle size distribution. Laser diffraction analysis reveals that optimal HLB values improve stability and reduce aggregation, ensuring a more uniform dispersion. Additionally, hydrophobic liquid additives are incorporated to enhance coating flexibility, successfully mitigating cracking at the fold without compromising barrier performance. Furthermore, the replacement of petroleum-derived latex binders with PHB and PHB-co-HHx in base coatings is explored, demonstrating improved adhesion and water resistance when modified with starch. Surface energy modification with petrolatum wax further refines coating uniformity and compatibility with various substrates, enhancing practical application. Finally, a comprehensive literature review assesses the potential of bioplastics in pharmaceutical packaging, reinforcing the viability of PHA-based materials as sustainable alternatives. Collectively, these findings provide a framework for optimizing biodegradable coatings, offering insights into their industrial applicability while addressing key challenges in stability, adhesion, and performance.