One-pot preparation of algae-based phase change fibers with a dynamic double network structure for enhanced strength and toughness

In order to broaden the application area of seaweed fiber, a dynamic double network structure of inorganic nanoparticles (VSNP) was designed. VSNP was used as the physical crosslinker, ammonium persulfate (APS) as the initiator, acrylic acid (AA) as the monomer, polyethylene glycol (PEG) as the phase change functional modification, and calcium chloride (CaCl2) was used as the coagulation bath. By utilizing free radical polymerization and wet spinning techniques, a strong and tough phase change seaweed fiber with a dynamic double network structure (PEG/CA/PAA-VSNP) was successfully prepared. The structure and properties of PEG/CA/PAA-VSNP fibers were characterized using a FTIR spectrometer, an electronic single fiber strength meter, a differential scanning calorimeter (DSC), a scanning electron microscope (SEM), an X-ray diffractometer (XRD), a contact angle tester and a thermogravimetric analyzer (TG). It was found that the mechanical and phase change properties of PEG/CA/PAA-VSNP fibers were significantly higher than those of calcium alginate (CA) fibers: when the contents of PAA and VSNP were 15 wt%, and 7 wt%, respectively, and the mass ratio of SA to PEG was 1 : 4, the breaking strength and breaking elongation of the modified fiber reached 3.47 cN per dtex and 13.97%, which were 72.64% and 69.34% higher than those of the CA fibers, respectively. The enthalpy of melting and enthalpy of crystallization were 36.22 J g(-1) and 35.19 J g(-1), respectively. Compared with the CA fibers, the hydrophilicity and heat resistance of PEG/CA/PAA-VSNP fibers have also been improved. Therefore, this study is expected to achieve the application of seaweed fibers in more fields.