Dispersibility study of eight types of nanofibrillated cellulose and their Hansen solubility parameters

Nanofibrillated cellulose (NFC) is widely utilized across various fields due to its excellent comprehensive properties. An important area of research focuses on developing high-performance composites by blending NFC with different media, including solvents and polymers. The dispersion of NFC within the medium plays a crucial role in determining the overall performance of these composites. Hansen Solubility Parameters (HSPs) are essential for assessing intermolecular interactions and predicting the dispersion of nanofillers. In this study, microcrystalline cellulose (MCC) was used as the primary raw material to prepare eight types of NFC using the TEMPO oxidation method. The dispersibility of these NFC variants in twenty-nine different solvents was evaluated through turbidity measurements, and MATLAB software was employed to fit and obtain the HSPs for each type of NFC. Further research revealed a significant inverse relationship between NFC diameter, which serves as an indicator of its size, and the dispersion parameter (δ_D) value. Additionally, as the -COOH content increased, the hydrogen bonding parameter (δ_H) value also increased. In contrast, no significant correlation was observed between the polar parameter (δ_P) value and the morphological structure of NFC. This research aims to expand the HSP database for nanomaterials, providing valuable guidance for selecting the most suitable medium for optimal NFC dispersion.