Development of Co-Axial fibres composed of CA (Mn 50,000) and PEGs (600 and 1000): evaluation of the influence of the coagulation bath

Rapid urbanisation and industrialisation have intensified the Urban Heat Is-land (UHI) effect, significantly increasing energy demand for thermal comfort. Urban buildings consume considerable energy throughout the year, which can be reduced by incorporating Phase Change Materials (PCMs) into building materials. PCMs effectively regulate temperature by storing and releasing heat as latent heat during phase transitions. However, to prevent leakage, PCMs can be encapsulated in co-axial poly-meric Phase Change Fibres (PCFs), representing an innovative approach in scientific research. This study optimised the coagulation bath and produced PCFs using commercial cellulose acetate as the sheath and polyethylene glycol (PEG 600 and 1000) as the core via the wet-spinning method. The first part of this work investigated the coagulation bath using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy(ATR-FTIR) analyses of the characteristic peak areas. In contrast, the second part examined the PCFs’ morphological, chemical and thermal properties using Bright-field microscopy, ATR-FTIR, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) techniques. The results demonstrated the successful production of PCFs with an optimised coagulation bath. Bright-field microscopy and ATR-FTIR confirmed the well-defined morphology and the presence of PEG in the fibre core. TGA analysis showed high thermal stability in the PCFs, with mass loss observed at high degradation temperatures, ranging from ~264 ◦C to 397 ◦C for the PCFs with PEG 600 and from ~273 ◦C to 413 ◦C for the PCFs with PEG 1000. Meanwhile, DSC analysis revealed melting points of ~12.64 ◦C and 11.04 ◦C, with endothermic enthalpy of ~39.24 ◦C and 30.59 ◦C and exothermic enthalpy of ~50.17 ◦C and 40.93 ◦C, respectively, for PCFs with PEG 600, and melting points of ~40.32 ◦C and 41.13 ◦C, with endothermic enthalpy of ~83.47 ◦C and 98.88 ◦C and exothermic enthalpy of ~84.66 ◦C and 88.79 ◦C, respectively, for PCFs with PEG 1000. These results validate the potential of PCFs for applications in building materials for civil engineering, promoting thermal efficiency and structural stability.