Improvement of Rot-retardant Properties of Jute and Jute Goods
fibres like jute possess high strength, modulus and moisture uptake and low elongation and elasticity. Because of its high natural strength and
robustness, jute has historically and traditionally been used mainly as
packaging material e.g. sacking, Hessian/burlap, etc. for agricultural and
industrial products. Jute sand bags have been another important area of its
traditional use. Food grade jute bags is a newer addition to the traditional
packaging materials of jute in view of the growing demand from the
consumers/end-users dealing in coffee, cocoa, hazel nuts, shelled nuts etc.
While jute hessian /burlap and sacking are primarily used as a packaging
material it is also being used in a number of other areas.
increasing awareness of environment, biodegradable natural fibres like jute
is increasingly being preferred as geo-textile/agro-textile products. Thus
jute based geotextiles especially for erosion control, soil consolidation,
vegetation growth, civil and road construction, etc. are getting importance
day by day. Similarly agro-textiles in the form of nursery sheets, squares,
liners, socks, pockets, sleeves etc. are becoming popular and commercially
Jute is a ligno-cellulosic bast fibre. The basic constituent of jute
is cellulose – the elements of which form the empirical formula (C6H10O5)n.
Both bacteria and fungi can decompose cellulose but are dependant on
moisture content. Resistance of
natural fibre like jute to microbial damage may be dependant upon the
physical properties (such as, crystalline, chain length, orientation of
ultimate cells etc.) and the chemical constituents (such as lignin, hemicelluloses, gummy materials etc.) The higher the lignin content the more
resistant the fibre will be to rotting i.e. fungal attack.
Jute products naturally decompose faster than what is required
for some applications like geo-textiles/agro-textiles, sandbags etc. This
quick biodegradability of jute based products especially on soil contact and
exposure to moisture/water is sometimes disadvantageous.
Biodegradation is a non-specific process and it can be started
in any space which is available to various organisms. Moreover, favorable conditions like heat, light, temperature, moisture, pH value, etc. also have
impact on the degradation. This biodegradation seems to occur through free
radical mechanisms of jute and jute products.
Quick biodegradation of jute products is advantageous in case
of its disposal after use especially in land filling/land reclamation etc.
More so since the degraded jute products have got definite fertilizing
effect through increasing soil nutrient and biomass.
Ordinarily when jute fabric is placed in intimate contact with
moist earth or soil, it degrades quite rapidly and degrades completely
within 2-3 months. In contrast, a dry sand-bag, filled with dry, clean sand,
if maintained in a dry clean state has a life of many months.
Since jute naturally decomposes faster than what would be ideally suited in a
number of applications the process of biodegradability of jute fabrics/Hessian/burlap
etc. needs to be retarded. The methods
protecting jute fabric against micro-biological attack depend on the
introduction of a substance into or on the surface of jute fibre/product so
that it acts as deterrent or provide toxicity to the micro-organisms and
prevents its reproduction and growth.
Past investigations have indicated that 0.5 - 2% copper content gives
maximum protection against rotting of jute products. The method that is long
being used aims at forming a basic carbonate of copper on the jute fibre.
The definite protective action of copper-ions impregnated in the
fabric has been proved from experimental data and field trials. It has been
found that the average life of sand-bags can be increased six fold when
treated with copper salts. This increased time/life of serviceability
justifies economic pre-treatment of sand-bags/other jute products before
Therefore, to retard the process of decomposition or increase
the durability of the jute products these need to be treated with copper
compounds like copper sulphate, copper ammonium sulphate, copper ammonium
carbonate, copper acetate, copper naphthenate, etc.
Since copper compound like copper sulphate is being used for
anti-microbial treatment or preservative for vegetables since long, details
of copper sulphate as an example is given below.
Copper Sulphate :CuSO4
Other Name : Blue Vitriol blue
Physical Chemistry: Mol. Wt. 249.7 (Pentahydrate)
Form: Blue Crystals
Soluble in water
Stability: Slowly efflorescent in Air
Mode of Action : Aquatic algicide and foliar fungicide with
the control of most species of algae in ponds, lakes, potable water,
fish hatcheries, rice fields, streams, ditches, swimming pools
as a general fungicide when mixed with lime to form Bordeaux mixture.
as a wood preservative.
/ Environment in soil, copper compounds are partly washed down to lower
levels, partly bound by soil components and partly oxidatively transformed.
the purpose of this treatment jute fabrics/ Hessian/ burlap is soaked in any
of the compounds mentioned above and dried to ensure that 0.75% to 1.5%
metallic copper is deposited on the fabric. It is this 0.75% to 1.5%
metallic copper content by weight on fabric on dry basis which acts as an
antimicrobial agent to protect the fabric from quick biodegradation. This
insignificant amount of metallic copper deposition is sufficient to impart
rot retardance to the fabric to protect itself without causing any harmful
effects to the environment, so far known.
A considerable degree of rot resistance is imparted to jute materials by
dipping them in a bath of a soluble copper salt such as copper sulphate.
There are other copper salts like copper acetate, copper ammonium carbonate,
etc. which can be used as well for the same purpose.
Copper under these conditions is taken up by jute in
appreciable amounts and is fairly resistant to the leaching action of water.
Copper, it is suggested, is bound by chemical/ physical combination with
certain reactive groups, present mainly in the non-cellulosic constituents
and lignin of jute. In view of the relative cheapness and ease of
operations, the treatment appears to offer practical possibility.
The binding of copper with jute appears to be due to its chemical/physical
combination with the fibre material. About 70% of the ash of jute is
cationic and these cations appear to be in combination with carboxyl groups
which mostly belong to the polyuronic acids. About one eighth of these
carboxyl groups appear to be free, three eighths combined with the cations
and one half esterified with lignin. It is probable that copper reacts with
free and bound carboxyl groups by replacing hydrogen and other cations. A
new complex of copper is thus formed.
The phenolic hydroxyl groups of tannins and lignin also bind copper.
Such chemically bound copper may manifest toxicity against rotting
It seems that during the rot proofing treatment of jute with copper sulphate or
any other copper compound, a new complex is formed by reaction of copper
compound with mainly non-cellulosic constituents and lignin present in jute.
The adverse effect of this new complex is not yet known to anybody or
documented so far. What is known is that this compound retards rotting of
jute during the storage and use thereby ensuring extended life for jute
product. This new complex of copper hitherto mentioned on soil
contact application will degrade under a different mechanism. So, copper
compounds can be used to treat jute for imparting extended life. Further the
amount of copper compound used in the treatment of the burlap / hessian is
not significant. In the nature, copper exits as copper sulphate, basic
copper carbonate, etc. Copper, as a metal, is generally considered harmless.