Non-freezing water sorbed on microcrystalline cellulose studied by high-resolution thermogravimetric analysis

Knowing the nature of water-cellulose interactions is a key factor in understanding cellulose properties and developing new processing strategies. The emergence of new advanced materials based on nanocelluloses requires more precise methods to study these systems. Here we described the study of water-cellulose interaction by high-resolution thermogravimetric analysis (TGA), comparing dynamic and auto stepwise methods. Auto stepwise method was able to identify with precision three different types of non-freezing water, which we denoted as, (I) weakly bound water, (II) intermediate and (III) strongly bound water. The Ozawa-Flynn-Wall method was used to estimate the activation energy of strongly bound water desorption, E-a average = 50.45 kJ.mol(-1) and the cellulose degradation energy, E-a average = 143.18 kJ.mol(-1). The results obtained provide a new knowledge about the interaction between water and cellulose since other techniques such as DSC are not sensitive to non-freezing bound water.

Automated summary

Understanding the nature of water-cellulose interactions is crucial for grasping cellulose properties and developing new processing approaches. Through high-resolution thermogravimetric analysis (TGA), researchers identified three types of non-freezing water using the auto stepwise method, providing new insights into water-cellulose interactions that traditional techniques like DSC may not detect. Activation energy for strongly bound water desorption and cellulose degradation energy were estimated using the Ozawa-Flynn-Wall method.