Recent Advances in Supercritical Carbon Dioxide Foaming Technology for Thermoplastic Polyurethane Foams: Process Optimization, Property Modulation, and Emerging Applications

Abstract

Supercritical carbon dioxide (ScCO2) foaming has emerged as a sustainable alternative to conventional chemical/physical blowing agents for fabricating thermoplastic polyurethane (TPU) foams. This review systematically explores recent advancements in ScCO2 foaming technologies, including batch, extrusion, and injection molding processes, with a focus on their impacts on foam morphology (e.g., cell density, size, expansion ratio) and performance (e.g., electrical conductivity, mechanical strength, and thermal insulation properties). Key factors such as temperature, pressure, and additive integration are critically analyzed to establish their roles in optimizing TPU foam structures. Furthermore, emerging applications in electromagnetic shielding, flexible sensors, and thermal management are highlighted, demonstrating the versatility of ScCO2-foamed TPU. By bridging process–property–application relationships, this work provides actionable insights for designing next-generation lightweight and functional polymer foams.