Optimization of Preparation Process and Properties Analysis of Soy Hull Nanocellulose Hydrogel

The preparation process of soy hull nanocellulose hydrogel was optimized by Box-Behnken response surface. The structure and properties of soy hull nanocellulose hydrogel were studied. On the basis of single factor experiment, the preparation process of soy hull nanocellulose hydrogel was optimized through response surface with three factors and three levels when the maximum stress was used as the index. The structure and properties of soy hull nanocellulose hydrogel were characterized by Fourier transform infrared spectroscopy, X ray polycrystalline diffractometer, scanning electron microscopy, UV spectrophotometer, etc. The optimal process parameters were as follows: gelling temperature 191 ℃, freezing time 102 h, CaCl₂ concentration 7%. Under this condition, the actual maximum stress of soy hull nanocellulose hydrogel was 84.11 kPa, which was close to the predicted value of 83.7 kPa. The nanocellulose of soy hull/sodium alginate/CaCl₂ (SCNFs/SA/CaCl₂) hydrogel showed uniform 3D network structure, excellent tensile performance (elongation at break was 220%), mechanical strength (83.97 kPa), transmittance (82%), and electrical conductivity (1.58 S/cm). The SCNFs/SA/CaCl₂ hydrogel also had excellent mechanical strength and fatigue resistance after five cycles of stretching, so the service life of hydrogel was increased. This study provides a new method for preparing a tough, transparent, conductive and fatigue-resistant nanocellulose hydrogel.