Date of Award

2026-05-01

Degree Name

Master of Science

Department

Metallurgical And Materials Engineering

Advisor(s)

David A. Roberson

Abstract

This study investigates development of Roman concrete-inspired self-healing polymer blends based on polyvinyl alcohol (PVA) and polylactic acid (PLA) for the additive manufacturing (AM) process of fused filament fabrication (FFF). The motivation for this work stems from the need to enhance durability and functionality of biodegradable polymers while addressing environmental concerns associated with plastic waste. Inspired by the multifunctional and hierarchical architecture of Roman concrete. PVA is integrated as a hydrophilic, sacrificial phase similar to lime clasts, embedded inside a PLA-rich structural matrix to promote physical interaction and water-activated self-healing behavior. Binary PVA:PLA blends with ratios of 5:95, 10:90, 20:80 weight percentage (wt%) were compounded and extruded into filaments. 3D print temperatures were optimized based on print quality across a processing temperature range of 190-220 °C. Printed specimens were fabricated using two raster pattern orientations of 0° and ± 45° to evaluate anisotropic mechanical behavior inherent to additively manufactured materials. A comprehensive characterization approach was utilized, that consisted of melt flow index (MFI) to asses flow behavior and processability; fourier-transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR) to examine chemical changes within the blends; tensile testing and dynamic mechanical analysis (DMA) to evaluate mechanical and thermal mechanical performance; and scanning electron microscopy (SEM) to analyze fracture morphology from fracture tensile specimens. Self-healing behavior was observed from three different methods with an addition of tensile testing to evaluate the effect of water interaction. The results demonstrate that the increase of PVA content had a significant influence on melt flow behavior, hydrogen bonding interaction, printability and mechanical response without evidence of chemical transformation. Composition-driven physical modification of the polymer network is shown by changes in FTIR spectrum features, fracture morphology and self-healing behavior, consistent with the proposed Roman concrete-inspired framework. Overall, this study established a sustainable approach to building multifunctional, self-healing polymer systems for additive manufacturing applications and demonstrates a processing-structure-property relationship for PVA:PLA mixes made using FFF.

Language

en

Provenance

Received from ProQuest

File Size

90 p.

File Format

application/pdf

Rights Holder

Stephanie Moreno

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