1070-4272/05/7809-1479+2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 9, 2005, pp. 1479!1485. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 9,
2005, pp. 1504!1510.
Original Russian Text Copyright + 2005 by Mikhailov, Lebedeva.
AND POLYMERIC MATERIALS
Preparation and Modification of Chitin-Based Fibers
G. M. Mikhailov and M. F. Lebedeva
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received April 21, 2003; in final form, July 2005
Abstract-Spinning solutions of chitin were modified with polyvinylpyrrolidone, methyl cellulose, and sulfite
cellulose. The resulting systems were used for preparing fibers by the wet formation method. The deformation
and strength characteristics of these fibers were determined, and their X-ray diffraction analysis was carried
out. The influence of the modifying additives on the structure and characteristics of the systems prepared
Biological activity of a natural polysaccharide,
chitin, makes it attractive for researchers in the con-
text of preparation and use of materials thereof, in par-
ticular, fibers. Chitin accelerates 334 times healing
of wounds, and chitin sutures give cosmetic seams
. Pilot sutures resolve in a patient’s body within
the period sufficient for complete healing of a wound.
However, inadequate elasticity of chitin sutures pre-
cludes commercial production of resolving chitin-
based surgical seam materials in world practice.
Sukhanova et al.  showed that brittle failure of
chitin-based sutures is due to easy crystallizability of
chitin. This property is exhibited by cellulose and
a number of others polysaccharides. One of the ways
to disturb the crystallinity of a chitin fiber is partial
deacetylation of chitin, increasing the structural in-
homogeneity of the suture.
An increase in the structural inhomogeneity of the
system under partial heterogeneous deacetylation of
chitin hinders crystallization of the polymer during
preparation of the fiber and increases its elasticity .
At chitin deacetylation degree of <0.30, the fiber
forms a knot and preserves 40% of its initial strength.
Heterogeneous deacetylation involves a severe impact
of a concentrated alkali (30350%) at a high tempera-
ture on chitin and frequently yields products with
difficultly reproducible characteristics. This makes
unreasonable the use of such a step in the technology
because of variable characteristics of the resulting
copolymer (solubility, gel formation, possible forma-
tion of glucuronic acids, etc.), which not only com-
plicates but frequently hinders preparation of spinning
solutions and formation of a fiber.
Therefore, it is necessary to develop a method of
structural modification suitable for hindering crystalli-
zation of the macromolecules of the polysaccharide,
chitin, increasing the elasticity of fibers, and extend-
ing the application field of such a valuable polymer.
We used the following chemicals: dimethylacet-
amide available from Vekton (it was dehydrated and
vacuum-distilled, with collection of the fraction boil-
ing at 42oC and a residual pressure of 7 mm Hg);
lithium chloride crystal hydrate (dehydrated at 400oC);
sulfite cellulose (Svetogorsk Paper and Pulp Com-
bine), DP = 996; crab chitin (manufactured by
Vostok-Bor Joint-Stock Company, Dal’negorsk), M =
170 kDa, without ash and proteins; chitin from the
North Sea shrimp, M = 135 kDa, with ash and proteins
removed; polyvinylpyrrolidone (PVP) (samples with
different molecular weights were prepared by radia-
tion-induced polymerization ); and methyl cellulose
with DP = 980 and degree of substitution 0.94 (labor-
Spinning solutions were prepared by dissolving
polymers in a dimethylacetamide + 5% LiCl mixture
so that the total concentration of chitin and the modi-
fying polymer was 3% [7, 8]. The desired systems
were obtained by introducing into the chitin solution
the required amount of the solution of the modifier,
which was followed by thorough mixing and gas re-
moval in a vacuum, whereupon the resulting mixture
was used for formation of fibers.
Fibers were obtained on a PIFV-01 setup, using a
dosing syringe and a 1/0.4 spinneret. For precipitation
served an alcohol bath, and for plasticization, a water
bath. The fibers were freed from LiCl by washing
with hot water until complete absence of chloride ions