The surface of cellulose nanocrystals, prepared by sulfuric acid hydrolysis of cotton, was rendered cationic through a reaction with epoxypropyltrimethylammonium chloride. The resultant nanocrystal suspensions were characterized by ζ-potential, conductometric titration and polarized light microscopy. Atomic force microscopy (AFM) showed no change in the size or shape of the nanocrystals, but the functionalization process reversed the surface charge and led to a reduction of the total surface charge density. These modifications led to stable aqueous suspensions of nanocrystalline cellulose with unexpected gelling and rheological properties. Shear birefringence was observed, but no liquid crystalline chiral nematic phase separation was detected.

The irradiation of pulp is of interest from different perspectives. Mainly it is required when a modification of cellulose is needed. Irradiation could bring many advantages, such as chemical savings and, therefore, cost savings and a reduction in environmental pollutants. In this account, pulp and dissociated celluloses were analyzed before and after irradiation by electron beaming. The focus of the analysis was the oxidation of hydroxyl groups to carbonyl and carboxyl groups in pulp and the degradation of cellulose causing a decrease in molar mass. For that purpose, the samples were labeled with a selective fluorescence marker and analyzed by gel permeation chromatography (GPC) coupled with multi-angle laser light scattering (MALLS), refractive index (RI), and fluorescence detectors. Degradation of the analyzed substrates was the predominant result of the irradiation; however, in the microcrystalline samples, oxidized cellulose functionalities were introduced along the cellulose chain, making this substrate suitable for further chemical modification.