Organizing co mmittee

 
 

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Poster presentation 
208 
OXIDIZED NANOCELLULOSE AND ITS APPLICATIONS 
M.M. Kuzieva, A.A. Atakhanov
 
Institute of Polymer Chemistry and Physics, Uzbekistan Academy of Sciences, 
Tashkent, Uzbekistan, 
e-mail: [e-mail] 
Nanocellulose (NC) is the most abundant natural polymer and versatile starting 
material for chemical modification for obtaining products with various applications. The 
oxidation of nanocellulose results in derivatives with improved properties, including the 
products with new, specific features that can be used for medical and pharmaceutical 
purposes. Due to its biocompatibility and biodegradibility, the oxidized cellulose (6-
carboxycellulose) is widely used as a hemostatic agent, as a barrier for the prevention of 
postsurgical adhesion, in bandage products for covering different wounds, as an 
excipient in the production of tablets, various gels and pharmaceutical suspensions. 
In this work, the possibility of NC oxidation in a more accessible way under mild 
conditions using potassium dichromate in an acidic medium was shown. The oxidation 
of NC proceeds at C6 carbon without the destruction of the pyranose ring of cellulose 
and the number of carboxyl groups of the ONC is 1.21–1.36 mmol/g. The appearance of 
a new peak (1721 cm
−1
) in the FTIR- spectra related to the C=O group was observed.
The thermal stability of oxidized nanocellulose (ONC) decreased compared to NC. It 
is revealed that an increasing of the oxidation process duration leads to decreases in the 
degree of crystallinity and thermal stability. Based on the results of the X-ray structural 
analysis, the sizes of both the crystallites and the unit cells of NC and ONC are 
calculated, where a decrease in size in one direction and an increase in size in the other 
two directions of measurement are observed. Theoretical calculations were carried out, 
and a model was created for the hydroxyl groups available for oxidation at carbon C6, 
which amounted to approximately 5% of the total number of hydroxyl groups of the 
elementary units in the crystallite. It was calculated that 60% of the available hydroxyl 
groups at carbon C6 were oxidized to carboxyl groups. The change of ONC degree of 
crystallinity (DC) from 88.0% to 82.5% was revealed and the sizes of the unit cells of 
both NC and ONC were calculated.
By using AFM and DLS it was shown that the oxidation process leads to a decrease 
in the particle size and a change in the shape of the particles from acicular to spherical, 
while the particle size distribution becomes monodisperse. The ONC samples are able 
to accumulate charge on their surfaces. The ONC formed by potassium dichromate 
oxidation has potential application as an environmentally friendly and cost-effective 
nanomaterial in energy-related fields. 
The AFM study showed that NC particles have an acicular shape with a width of 20–
80 nm and a length of 180–600 nm. The oxidation process leads to a decrease in the size 
of particles with a width of 50–120 nm and a length of 150–400 nm and partial 
destruction of the acicular shape of NC with a transition to a spherical shape. An 
increase in the time of the oxidation process leads to the formation of agglomerates of 
spherical particles with a size of 20–60 nm. 
ONC was synthesized using potassium dichromate as an oxidizing agent. Data 
analysis shows that oxidized nanocellulose products have wide application in industry, 
in particular in medicine.