A preparation
process of cellulose nanocrystals using a Fenton-like
system was presented. Rod-shaped cellulose nanocrystals were isolated
after treatment in the H2O2/acetic acid/2–6
mol % copper acetate system. The morphology and sizes of rod-shaped
particles were determined by AFM (atomic force microscopy) and cryo-EM
(cryo-electron microscopy). X-ray diffraction proves that the prepared
particles have a natural polymorphic modification of cellulose I with
a high crystallinity index. Thermogravimetry data indicates a slight
decrease in thermal stability of the particles when compared to starting
cellulose, correlating with an increase in the number of carbonyl
groups determined by chemical analysis. Using pK spectroscopy,
active acid–base surface sites (pK
i 5.5 and 7.9) were quantitatively determined. The cellulose nanoparticles
formed stable hydrosols. Using photometry and dynamic light scattering,
it has been established that the critical concentration of coagulation
of sols is 76 mM KCl.