Comparative Network Design of Nanocellulose–Alginate Hydrogels with Enhanced Release and Shrinkage Resistance

Natural sodium alginate hydrogels have low active ingredient release rates and significant volumetric shrinkage. Usually, a stable skeletal structure needs to be introduced to maintain the stability of the gel. In this study, four types of environmentally friendly nanocellulose (prepared via mechanical, enzymatic, acid hydrolysis, and oxidation methods) were incorporated into sodium alginate matrices to modify the gel network structure. Leveraging the gelation mechanism of sodium alginate and the regulatory influence of nanocellulose, a calcium ion-nanocellulose interpenetrating network was established at the microscopic level. The compatibility and reinforcement effects of different nanocellulose types were compared systematically, discovering that when the addition of micronano cellulose MCNF, obtained through ultrafine grinding, was 0.8%, the gel mask achieved an antishrinking rate of over 50%, an encapsulation efficiency of 56.73%, a release rate of 45.90% at 15 min, and an effective release rate of 26.04%, laying the foundation for further expansion of the application of mmicronano cellulose and SA.