Университети кимё – технология факультети

THERMODYNAMIC STABILITY OF THE SYSTEMS BASED ON THE 
WATER-SOLUBLE ESTERS OF CELLULOSE 
a
Akbarov Kh.I., 
a
Kattaev N.T., 
a
Yarkulov A.Yu., 
a
Umarov B.C., 
b
Rakhmanberdiev G.R. 
a
National University of Uzbekistan named after Mirzo Ulugbek
 
b
Tashkent Chemical-Technological Institute 
e-mail: 
[e-mail]
 
Compositions on the base of water-soluble acetate cellulose (WSAC) and 
collagen are presented interest as films and spongy resolving materials in 

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callogenoplastics. Sorption investigations of compositions have shown that 
isotherms of sorption of water steams by samples of WSAC and collagen and their 
mixtures of different composition have S-figuratively type. Initial samples of 
WSAC and collagen have the most sorption ability. For mixtures of WSAC-
collagen in all interval of relative pressures a low sorption ability has been 
observed in comparison with initial polymers. In this case interaction of polymer-
polymer was prevailed under interactions polymer-solvent that is the phenomenon 
of compatibility of macromolecules of different nature was observed. Middle free 
energies of mixing polymer-solvent Δg
m
and values of Δg
m
max
are less negative 
what has indicated on decreasing of interactions polymer-solvent and increasing of 
intermacromolecular interactions components of different chemical nature. On the 
base of sorption isotherms of water steams values of parameter Flory-Haggins 
characterizing interaction of polymers with solvent were calculated for samples 
WSAC-collagen of different compositions. Investigation has shown that 
compositions have more higher values of parameter χ in comparison with initial 
WSAC and collagen what has indicated on worsening of interaction of solvent 
with mixtures of different compositions. It was shown that values of the middle 
free energy of mixing polymer-solvent Δg
m
and Gibbs energy ΔG in the case of 
systems WSAC-collagen at ratios of components 1:1 and 3:1 were less negative 
but values of parameter of interaction polymer-solvent Flory-Haggins at middle 
relative pressures of water steams were more positive in comparison with initial 
polymers. 
Analysis of experimental data according to theory Zimma-Landberg has 
been carried out and it gave information about mechanism of sorption of water 
steams and has allowed to valued trends to formation of clusters of water 
molecules in process of there absorption by polymers. Results of investigations 
have witnessed that for investigated samples cluster-formation was observed only 
in range of middle activity of water steams what is coordinated with literature data 
by claster formation by hydrophilic polar polymers. Cluster formation in range of 
relative low pressures is connected with formation of hydrogen bonds polymer-
water and water-water.Adsorption theory of De Bur and Zviker elaborated for 
processes interaction of polymer sorbates with polar sorbents can be used for 
systems WSAC-collagen-water. It can be used for processes of water bonding as 
adsorption and absorption mechanisms. Results of experimental checking of 
equation of De Bur and Zviker have shown linearization of isotherm of sorption of 
water steams and allowed to determine value of “true” sorption didn’t complicated 
by capillary condensation and clusterization of water. Values of the middle free 
energy of mixing polymer-polymer Δg
x
were calculated by method of Tager which 

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for all compositions of mixtures WSAC-collagen were negative what is witnessed 
about thermodynamic stability of investigated systems. Conclusions obtained on 
the base of calculations Δg
x
from composition of mixtures WSAC-collagen were 
proved by calculations of parameter of interaction in system polymer-polymer-
solvent by theory of mixing Flory-Scott. 
In medical ratio system NaCMC-dextran is interested. It is known that 
solutions of dextran are used as thermodynamic mediums. Water-soluble CMC has 
promoted to increasing and prolongation of dextran properties and by this reason it 
is important to have data about thermodynamic compatibility of this system. 
Mixtures of NaCMC and starch are very perspective because they can be used as 
biodegraded systems.