1070-4272/05/7806-0967 C 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 6, 2005, pp. 967!970. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005,
Original Russian Text Copyright + 2005 by Suvorova, Tyukova, Smirnova, Tymchishina.
AND POLYMERIC MATERIALS
Rheological Properties of Blends of Ternary
Copolyamide 6/66/610 with Chitosan
A. I. Suvorova, I. S. Tyukova, E. A. Smirnova, and N. M. Tymchishina
Gorky State University, Yekaterinburg, Russia
Received November 25, 2004; in final form, March 2005
Abstract-The viscosity of melts of a blend of a ternary copolyamide 6/66/610 and polysaccharide (chitosan)
used as biodegradable additive was determined by capillary viscometry at 1503170oC.
Properties of blends of synthetic and natural poly-
mers are studied to develop new environmentally clean
materials temporarily used in homes, agriculture, and
cosmetic and medical industry. The natural polymers
contained in these blends promote degradation of
the composite under the action of H
soil moisture, microorganisms, fungi, worms, and
other biological and chemical agents causing degrada-
tion of polymers with subsequent decomposition of
the disposed articles. Starch is most frequently used
as a biodegradable component of polymer composites.
Starch is a plant polysaccharide which readily degrades
under the physiochemical and biological action of
the environment [1, 2]. Another natural polysaccha-
ride, chitin, produced by Crustacea, insects, and other
living things, can also be used for this purpose. Chitin
is a renewable natural polymer accumulated in large
amounts. However, it is used to a lesser extent than
starch [3, 4]. The acetamide group of chitin can be
readily hydrolyzed to form chitosan, which is a co-
polymer of (2-amino-2-deoxy)- and (2-acetamido-2-
deoxy)-b-1,4-D-glucans. Chitosan and chitin are bio-
degradable polymers . The solubility of chitosan
and its miscibility with other polymers are higher than
those of chitin owing to formation of inermolecular
hydrogen bonds between the components or of ion-
polymer complexes with polyelectrolytes . There-
fore, blends of synthetic polymers with chitosan should
be of practical interest.
Here we studied the rheological properties of chito-
san blends with synthetic copolyamide (SPA) used in
production of films and hot-melt adhesives. The mis-
cibility of these polymers should be promoted by for-
mation of hydrogen bonds between the amide groups
3NH3CO3 of the SPA macromolecule and chitosan.
Previously, we have shown  that SPA forms homo-
geneous blends with starch in the presence of plasti-
cizers (glycerol and water) providing the compatibility
of the polymers (so-called compatibilizers). The sim-
ilarity between the rheological properties of these
blends and those of common synthetic polymers makes
these mixtures promising for practical applications.
A specific feature of the SPA3chitosan blend is that
only relatively reactive compounds like acetic or for-
mic acids are suitable as compatibilizers for these com-
ponents. In this study, we used polymer blends free of
these additives. The copolyamide served as a matrix,
and chitosan, as a filler providing biodegradation of
the composite. We used ternary copolyamide 6/66/610.
Since the melting point of the copolyamide was lower
by approximately 100oC than the temperature of ther-
mal degradation of chitosan, the blends were prepared
by direct addition of chitosan to an SPA melt.
Since the processing conditions of a polymer blend
are determined by its rheological properties (viscos-
ity), we studied the temperature dependence of the vis-
cosity of chitosan3copolyamide melts as influenced
by the chitosan content of the blend.
We studied blends of ternary copolyamide 6/66/610
with chitosan. The copolyamide was prepared by co-
condensation of caprolactam, and AG and SG salts
taken in a 45/10/45 weight ratio. The molecular weigh
and the degree of substitution of chitosan, determined
by the procedure described in , were 1.2 0 10
89%, respectively. We used polymer powders with
a particle size of about 7 0 10
m. Chitosan was X-
ray-amorphous, and the degree of crystallinity of SPA