Plant protein in material extrusion 3D printing: Formation, plasticization, prospects, and challenges

Abstract

Use of plant proteins for material extrusion 3D printing presents an exciting opportunity to expand current material and additive manufacturing applications. Plant protein-based materials possess attractive thermomechanical properties, which make them prospective sources for use in 3D printing. This review provides insights into the current state of protein-based material properties, specifically in the context of material extrusion 3D printing applications. Information is drawn from the literature on protein-based film formation via casting, compression, and extrusion, as well as material characterization and modifications. Material formation and plasticization are discussed, and current material formation and characterization methods are reviewed. Mechanical and thermal properties are examined and considered with respect to processing conditions and plasticizer-protein interactions, using soy and zein protein as model systems, and are related to 3D printing conditions and material requirements. Alternative feed proteins are also examined based on their material properties, and prospective protein sources for extrusion 3D printing are identified. Challenges in using plant proteins as materials for extrusion 3D printing include high moisture uptake, 3D printing inherent operating conditions, and plasticizer selection. Chemical and physical modifications are reviewed that could potentially address these challenges.