ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 11, pp. 1928!1930. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + V. Grazuleviciene, L. Augulis, J.V. Grazulevicius, P. Kapitanovas, J. Vedegyte, 2007, published in Zhurnal Prikladnoi Khimii,
2007, Vol. 80, No. 11, pp. 1904 !1907.
AND POLYMERIC MATERIALS
Biodegradable Starch, PVA, and Peat Composites
for Agricultural Use
V. Grazuleviciene, L. Augulis, J. V. Grazulevicius, P. Kapitanovas, and J. Vedegyte
Lithuanian University of Agriculture, Kaunas Region, Lithuania
Kaunas University of Technology, Kaunas, Lithuania
Received July 16, 2007
Abstract-Mechanical and sorption properties of starch-, PVA-, and peat-based composites for fabricating
planting containers are studied.
Because of their lightness, good mechanical proper-
ties, and low cost, polymeric materials are widely
used in agriculture. Diverse polypropylene, polyethyl-
ene, or polystyrene containers are used in hothouse
and lawn-and-garden farming for plant seeding,
prickling-out, and growing. However, in contrast to
other materials, synthetic polymers are not biodegrad-
able under natural conditions [1, 2]. Recycling of
plastics is cost expensive, and the essential part of
plastic wastes is fired or dumped, thus deteriorating
the environmental situation [3, 4]. The problem of
utilization of plastic wastes may be eliminated, if
using containers fabricated from biodegradable ma-
terials, such as peat- or cellulose-based composites.
It is known [5, 6] that biodegradable polymers
combine good mechanical properties of synthetic
polymers with easy biodegradability of natural poly-
mers. Among such materials are hydroxy carboxylic
acid based polymers, polyvinyl alcohol (PVA), com-
mercial polymers (polyethylene and polypropylene)
functionalized to make them biodegradable, and also
composites of the indicated polymers with biodegrad-
able additives [7, 8]. However, the cost of these ma-
terials is much higher as compared to large-tonnage
commercial synthetic polymers, thus reducing the
potentiality of their agricultural applications.
Composite materials based on renewable natural
polymers (starch, cellulose, proteins) with various
additives are used in agriculture , most well-
known among them are starch-based composites .
Presently, the primary issue is the problem of com-
patibility of components, which is critical not only for
performance characteristics of the resulting materials,
but also from the technological standpoint.
In this study, we examined mechanical and sorp-
tion properties of polymeric composite materials
based on starch, PVA, and peat.
For fabrication of biodegradable composites we
used potato starch (Lach-Ner, Czech Republic), poly-
vinyl alcohol Mowiol 23-88 (Kuraray Specialities
Europe), glycerol (Barta a Cihlar, Czech Republic),
and peat pots (Floryn, Poland).
Test samples were prepared as follows. A solution
containing starch and PVA (see table for the solution
composition) was stirred at 80oC for 60 min until
gelation, and glycerol (4%) was added. From the
resulting mixture, films were formed (10-ml portions
were cast into Petri dishes 10 cm in diameter and
dried at 40oC). Peat-based composites were prepared
by impregnation of plates cut from peat pots in the
resulting mixture at 80oC for 5 min, followed by dry-
Composition of polymers
³ Concentration in solution, %
³ starch ³ PVA
1 ³ 10 ³ 0
2 ³ 8 ³ 2
3 ³ 6 ³ 4
4 ³ 4 ³ 6
5 ³ 2 ³ 8
6 ³ 0 ³ 10