Porous Composite Films of Sodium Alginate and Polyacrylonitrile: Preparation and Moisture‐Absorbing and Heat‐Generating Performance

ABSTRACT With the advancement of functional textiles, polyacrylonitrile (PAN) is widely used in cold‐proof fabrics for its excellent thermal insulation but suffers from inherent hydrophobicity causing stuffiness during wear. Sodium alginate (SA), a natural polysaccharide rich in hydrophilic groups (‐OH, ‐COO − ), boasts outstanding moisture absorption and biocompatibility. This study developed SA/PAN composite films as a basis for functional fibers, preparing eight samples by adjusting SA concentration (0%, 1%, 2%), coagulation time (30 and 60 s), calcium chloride (CaCl 2 ) addition, and drying method (freeze‐drying/room‐temperature drying). Comprehensive characterizations (SEM, FT‐IR, porosity, etc.) revealed SA and PAN form composites via physical blending and Ca 2+ cross‐linking. Freeze‐drying is key for aerogel‐like porous networks, with sample 2601 (2% SA, freeze‐dried, no CaCl 2 ) achieving ~75% porosity. Sample 2610 (2% SA, room temperature dried, with CaCl 2 ) showed optimal hygrothermal performance (14.7% moisture regain, 133.79 J/g integral heat). High SA concentration constructs a porous skeleton, CaCl 2 enhances hydrophilicity through “hydrogen bonding + ion‐dipole” synergy, and freeze‐drying prevents pore collapse. This work elucidates the process control principles of the SA/PAN composite system, providing vital data and theoretical support for optimizing the wet‐spinning process of moisture‐absorbing and heat‐generating fibers.