Effects of repeated freeze-thaw cycles on the mechanical and structural properties of cellulose nanofiber and poly(vinyl alcohol) hydrogels

• Published in: Cellulose (London) Vol. 31; no. 12; pp. 7479 - 7492
• Main Authors: Takeno, Hiroyuki, Narita, Takumi, Hsieh, Wen-Chuan, Saito, Kiyotaka, Ku, Yu-Tzu, Su, Yu-Chieh, Inoguchi, Hiroki
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.08.2024; Springer Nature B.V
• Subjects: Alcohol; Biomedical materials; Bioorganic Chemistry; Borax; Cellulose; Cellulose fibers; Ceramics; Chemistry; Chemistry and Materials Science; Composites; Crosslinking; Elongated structure; Fluorescence; Freeze thaw cycles; Glass; Hydrogels; Mechanical properties; Nanofibers; Natural Materials; Organic Chemistry; Original Research; Physical Chemistry; Polymer Sciences; Polyvinyl alcohol; Reagents; Stem cells; Stretchability; Sustainable Development; Tensile strength; Composite hydrogel; Tearing energy; Cell scaffold; Freeze-thaw cycles; Cellulose nanofiber
• ISSN: 0969-0239; 1572-882X
• DOI: 10.1007/s10570-024-06087-1

In this study, we investigated the effects of repeated freeze-thaw cycles on the mechanical, and structural properties of cellulose nanofiber-reinforced poly(vinyl alcohol) composite hydrogel with borax as a crosslinking agent. Repeated freeze-thaw cycles significantly improved the mechanical performance of the composite hydrogels and enhanced the gel fraction. They improved not only the mechanical strength but also the stretchability of the composite hydrogels: the composite subjected to five- and ten-FT cycles exhibited an elongation of ~ 1100% and a tensile strength of 2 MP. In addition, the composite hydrogels exhibited tearing energies of 2.8–6.6 kJ m −2 , which are a few hundred times larger than those of normal hydrogels (~ 0.01 kJ m −2 ) and are comparable to those of double network gels known as tough gels (typically 1–3 kJ m −2 ). Repeated freeze-thaw cycles greatly contributed to the development of poly(vinyl alcohol) crystals and the formation of porous polymer networks, which are suitable for biomaterials, such as cell scaffolds. Fluorescent microscopy revealed the adhesion of cells on cellulose nanofiber/poly(vinyl alcohol) composite hydrogels cultivated with umbilical cord mesenchymal stem cells.