Leveraging Additive Manufacturing and Polymer Solution Thermodynamics to Advance Sustainability

Abstract

Understanding material interaction with fluids in complex systems is important for applications ranging from mineral precipitation in sub-surface systems to polymer separation in recycling processes. These interactions are difficult to predict due to the inherent heterogeneity and complexity of the systems. In this dissertation, controlled experimental approaches were developed to understand both reactive transport and polymer solution phase behavior. High impact polystyrene films were surface functionalized and were analyzed to understand surface energies associated with the films that help with mineral precipitation. This knowledge was then extended to develop a 3D model of a porous media (Benthemier sample) with controlled surface functionalization to promote calcite precipitation from saturated solutions. This showed that the increased surface energy aids to increased mineral growth and measurable porosity reduction in the 3D printed replicas of the porous media as confirmed by X-ray diffractions and X-ray micro-CT imaging. In parallel, the cloud point behavior of ethylene vinyl alcohol (EVOH) copolymer with varying ethylene content in dimethyl sulfoxide (DMSO) and DMSO/water systems was investigated. This research demonstrated that higher ethylene content in EVOH shifts the onset of phase separation to a higher temperature or pressure and enabled the construction of a practical working phase diagram for selective polymer recovery. Together, this dissertation demonstrates how engineered porous media, surface chemistry, and polymer solution thermodynamics could be combined to better understand and control material-fluid interactions, thereby improving understanding of subsurface geochemical systems and sustainable solvent-based polymer recovery and recycling.