(512a) Advancing Supercritical Fluid Technologies for Sustainable Fabrication of Paper Packaging Substrates

The negative impacts of plastic-based food packaging on the environment and human health are increasingly apparent. Plastic packaging, made from synthetic petro-polymers like polyethylene (PE) and polypropylene (PP), significantly contributes to waste plastics (40% of total plastic consumption) and has low recyclability rates (8% in North America). Additionally, these materials are non-biodegradable and contain chemical additives that can migrate into food, leading to health issues such as carcinogenicity and endocrine disruption. These concerns have prompted governmental interventions to support sustainable packaging paradigms, with mandates for all packaging to be reusable or recyclable by 2030 in the EU and California.

Natural polymers derived from biomass, such as cellulosic fibers in paper-based substrates, offer a renewable, abundant, and biodegradable alternative for sustainable packaging. However, their porous and hydrophilic nature limits their barrier resistance to moisture, necessitating integration into multilayer composites or coating with materials like polyethylene or PFAS, which pose environmental and health challenges. Therefore, advancing manufacturing technologies that enhance the moisture resistance of cellulosic fibers with eco-friendly additives are needed to support sustainable packaging initiatives.

Supercritical impregnation (SCI) is an emerging green chemistry method for modifying polymeric substrates using supercritical fluids (SCFs), primarily CO₂, to facilitate additive sorption. This presentation expands insights on SCI of paper substrates by systematically evaluating the influence of SCI process conditions, co-solvent effects, and intermolecular associations of eco-friendly additives and cellulosic fibers. We evaluate SCI-sorption mechanisms of small molecules and polymeric additives and their influence on the resulting barrier properties of packaging substrates. We characterize the molecular and crystallographic properties of the prepared substrates and their relationships with surface hydrophobicity and water vapor sorption kinetics, informing SCI engineering principles for sustainable packaging.