Date of Award

Summer 8-7-2025

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science in Chemical Engineering (MSChE)

Department

Chemical Engineering

First Committee Advisor

Douglas W. Bousfield

Second Committee Member

Colleen C. Walker

Third Committee Member

G. Peter van Walsum

Abstract

Majority solid marine litter consists of single-use packaging. Paper, a biodegradable and recyclable alternative, lacks crucial barrier properties essential for food preservation. Per- and polyfluoroalkyl substances (PFAS) are commonly used as paper coatings due to their exceptional barrier properties, which stem from their strong chemical bonds, compromising biodegradability. Traditional plastic films like polyethylene (PE) used in paper packaging are challenging to recycle, often remaining in landfills after paper decomposition. Seaweeds have emerged as a promising substitute. In this study, seaweed powder (Kappaphycus alvarezii) was used due to its high polysaccharide content. When mixed with glycerol as a plasticizer, it forms a viscous gel when dissolved in water around 80°C. This gel is cast on a plastic tray and dried overnight. Tensile tests revealed a good tensile strength of 0.6 MPa and 50% elongation at break. Seaweed gel applied to paperboard exhibited excellent oil and grease-resistant properties, with the kit test value increasing to 12 at 19 g/m² of coat weight and the water vapor transmission rate decreasing from 417 g/m²day to 330 g/m²day. To enhance moisture barrier properties, various hydrophobic agents were incorporated since seaweed is inherently hydrophilic. Water vapor transmission rate (WVTR) revealed that seaweed coating underneath significantly protects barrier properties when folded or creased, as observed for all hydrophobic agents used. Preliminary Technical and Life cycle analyses have revealed that the key issues were the cost of raw materials and the energy required to dry. This information can be crucial for further optimization. Although seaweed application increased overall hydrophilicity for certain coating agents, SEM images and Gurley tests demonstrated a continuous coating surface with low air permeability. This means that a novel coating method has been successfully developed to uniformly coat seaweed on the surface of paper without any extensive extraction processes. This work holds the potential to sustainably produce food packaging materials using simple and eco-friendly processes.

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