The effect of freezing speed and hydrogel concentration on the microstructure and compressive performance of bamboo-based cellulose aerogel

Cellulose aerogel is a kind of ultra-light solid material which resulting from natural cellulose materials, and its performance is highly related to its structure. In this study, we prepared cellulose aerogels with different densities by regulating the concentration of microfibrillated cellulose (MFC) hydrogel using bamboo parenchymal cells as a starting material. The effects of the freezing speed and hydrogel concentration on the microstructure and compression performance of the resultant aerogels were investigated. The results demonstrated that higher freezing speed can inhibit the aggregation of MFC, resulting in aerogel with higher porosity. Conversely, increasing hydrogel concentration facilitated the aggregation of MFC, generating a distinct conversion from a looser fibril network structure (low density) to a more compact sheet-like structure (high density). Moreover, the results showed an expected positive correlation between the density of the aerogel and its compression performance, both in compression modulus and energy absorption.