Changes in the structure of cellulose aerogels with depolymerization

To compare the cellulose aerogels from hydrolyzed and unhydrolyzed cotton linter, we prepared cellulose wet gels from cellulose solution dissolved in hydrated calcium thiocyanate at 110 °C and dried them by using the freeze-drying method. The initial root-mean-square (RMS) radius and the weight average molar mass of cotton linter decreased from 71 nm and 405 kg·mol ⁻¹, respectively, to 13 nm and 35 kg·mol ⁻¹ upon acid hydrolysis. The density of cellulose aerogels increased from 39 to 87 kg/m³ as the cellulose starting material was depolymerized. The microstructure of the cellulose aerogel was viewed with a scanning electron microscope (SEM), and the microstructure and the micro-sized pores were found to be destroyed by cellulose degradation. The degree of polymerization (DP) of the cellulose was found to affect the aerogel’s density and network structure.