Evaluating the dyeability of emerging sustainable polyesters and integrating dyeing and moisture management finishing in one-step waterless supercritical CO₂ process

Abstract

With the emergence of biodegradable/compostable polyester fibers, assessing their compatibility with existing dyeing and processing technologies remains a critical yet underexplored factor in their industrial adoption. This study evaluates the dyeability of conventional polyester (vPET), compostable polyester (cPET), and biodegradable polyester (bPET) using both conventional aqueous and waterless supercritical CO₂ (scCO₂) dyeing. In addition, the feasibility of integrating dyeing and moisture-management finishing into a single scCO₂ process was investigated using biodegradable polyester as a representative substrate and two commercial hydrophilic finishing agents, Feran ICS and Arristan rAIR. All polyester variants achieved high color strength and excellent color fastness properties in both dyeing media, demonstrating compatibility with established polyester coloration technologies. Among the tested materials, biodegradable polyester exhibited the highest apparent color yield (K/S value of 23.4) at 1% dye concentration. The integrated scCO₂ dyeing and finishing process successfully enhanced moisture-management performance, with Feran ICS providing greater improvements than Arristan, increasing the Accumulative One-Way Transport Index (AOTI) by +222% and the Overall Moisture Management Capacity (OMMC) by +138% relative to the untreated fabric. Although finishing treatments reduced air permeability slightly, the fabrics retained good breathability and maintained their functional performance after repeated laundering. These findings demonstrate the technical feasibility of processing emerging sustainable polyester variants using both aqueous and scCO₂ dyeing systems and highlight the potential of scCO₂ technology as a water-free platform for simultaneous coloration and functional finishing. The study provides a foundation for the broader adoption of sustainable polyester materials and more resource-efficient textile processing strategies.