FIELD OF THE INVENTION
This invention relates to grafted amylopectin for use in
sprinkler irrigation systems.
OBJECTS OF THE INVENTION
An abject of this invention is to propose grafted amylopectin for
use in irrigation sprinkler systems.
Another object of this invention is to propose grafted
amylopectin for use in irrigation sprinkler systems which
provides a substantial saving in power.
Still another object of this invention is to propose grafted
amylopectin for use in irrigation sprinkler systems which
enhances the throughput and area of coverage.
Further objects and advantages of this invention will be more
apparent from the ensuing description.
BRIEF DESCRIPTION OF THE INVENTION
According to this invention there is provided a process for the
preparation of a graft copolymers for use as a high performance
flocculating agent, comprising preparing a solution of
amylopectin and adding acrylamide monomer thereto with stirr.ing,,

fallowed by addition of a a catalyst such as cerium (TV) solution compound,thereto, and allowing
the reaction to continue, to obtain the graft copolymer.
In accordance with this invention, the catalyst used may be
compounds of inter-transition elements such as Cerium (IV),

preferably cerric ammonium nitrate, and the acrylamide may be a
substituted or unsubstituted aery1 amide compounds. The reaction
is generally carried out at a temperature in the range of 27 to
a o
32 C, preferably 30 C and is conducted for 20 to 30 hrs.,
preferably at 24 hrs., at atmospheric pressure.
The amylopectin is used in a proportion of 20 to 30 gms per 1.5
to 2.5 males of acrylamide. The catalyst is used in a proportion
of 1.5x10 to 2x10 moles per 20 to 30 gms of amylopectin.
The invention will now be explained in greater detail with the
help of the fallowing non-limiting example:
EXAMPLE
0.0154 mole (calculated on the basis of anhydroglucose units) of
amylopectin was put into a conical flask with 100 cc of distilled
water. The flask with a magnet in it was put on a magnetic
o
stirrer plate. The suspension was heated to 80 C with
simultaneous stirring and maintained at that temperature till
there was a distinct colour change and amylopectin went into
solution. It was cooled down to room temperature. Then 0.21 mole
of acrylamide CAM) was dissolved in 75 cc of distilled water and
was mixed with the amylopectin solution. Then the conical flask
was fitted with the nitrogen inlet and outlet tubes and oxygen
free nitrogen was purged through the solution for 20 minutes. At
this stage, 25 cc of catalyst solution (0.22 g of CAN in 100 cc
of distilled water) was added to the reaction mixture, followed
by further purging with nitrogen for 10 minutes. Then the
nitrogen inlet tube was taken out and the flask was sealed. The
polymerization had already started by this time which was evident
from the slower motion of the magnet. The temperature showed an
increasing trend but the flask was suitably placed in a water
o
bath to maintain the temperature at 30+13.1 C. The reaction was
allowed to continue far 24 hours. At the end of the reaction, the
resulting polymer mas taken out into a 1 L beaker where it was
made into a homogeneous slurry with further addition of distilled
water. The reaction was terminated by adding a saturated solution
of hydroquinone. The viscous polymer slurry was then precipitated
part by part in acetone to ensure complete precipitation. The
precipitated polymer mass was kept in acetone overnight. Next day
o
it was transferred to a vaccum oven and dried at 70 C for about
60 hours. Afterwards it was pulverized and sieved Cmesh size 52
(295 rm), test sieve BSs 410/603.
The amylopectm-g-acrylamide copolymers were then characterised
by the measurement of their inrinsic viscosity.
Intrinsic viscosity of all the graft copolymers was determined
from the intersection of two extrapolated (to zero concentration)
plots i.e inherent viscosity vs. concentration and reduced
viscosity vs. concentration. The Ubbelohde capillary viscometer
(CS/S= 0.00527) was used 0.5 gram of the polymer was dissolved
in freshly prepared distilled water with very slow stirring (so
as to avoid the settling of polymer granules at the bottom of the
flask). Ap-g-PAM, to obtain a series of graft copolymers with
varying number and length of polyacrylamide chains. The synthetic
details of all the graft copolymers, viz. starch-g-polyacrylamide
(Bt-g-PAM0, amylose-g-polyacrylamide (Am-g-PAM) and the series of
graft copolymers of amylopectin-g-polyacrylamide (Ap-g-PAM),
namely Ap-g-PAM 1 to Ap-g-PAm S are outlined in table I.
a. Calculated on the basis of anhydroglucose units (A6U). One
mole of AGU = 162 grams.
b. % Conversion was calculated from the reaction.
'/.Conversion = Wt .of draft copolymer z. Wt. of polysaccharide
Wt. of acrylamide monomer
The flocculation behaviour of the graft copolymers are studied
and Figs 1 of the accompanying drawings show the results of such
studies.
The copolymer used for these studies have been injected through
the suction end of the pump in a sprinkler irrigation system.
Fig. 1 shows the effect of commercial guargum on drag reduction,
power reduction and increase in area of coverage at flow rate of
420 lit/min incase of Inlet injection.
Fig. 2 shows the effect of purified guargum on drag reduction,
power reduction and increase in area of coverage at flow rate of
420 lit/min incase of Inlet injection.
Fig. 3 shows the effect of Ap-g-PAM on drag reduction, power
reduction and increase in radius of coverage at a flow rate of
420 1/min in case of inlet injection system.
Table II shows a comparative study of the effect of commercial
and purified guargum on drag reduction, power reduction and
increase in area of coverage and Table III shows a study of the
effect of grafted starch and grafted amylopectin on drag
reduction, power reduction and increase in area of coverage.
Therefore, it is apparent that the grafted amylopectin gives
maximum in drag reduction (34*/.), reduction in energy requirement
(24*/i) at 100 ppm and increase in area of coverage (17.8*/.) at 200
ppm of concentration by inlet injection system. These results are
of great significance because the maximum in drag reduction,
reduction in energy requirement and increase in area of coverage
are being obtained at higher level at l/3rd and l/7th of the
cencentrations of polymer solutions in comparison with purified
and commercial guar gum.
WE CLAIM:
1. A process for the preparation of a graft copolymer for use as
a flocculating agent comprising preparing a solution of the
polysaccharide and adding acrylamide thereto with stirring,_

followed by addition of a solution of a catalyst such as cerium (IV) thereto and allowing compound ,
the reaction to continue, to obtain the graft copolymer.
2. The process as claimed in claim 1 wherein the acrylamide is a
substituted or unsubstituted acrylamide.
3. The process as claimed in claim 1 wherein the catalyst is a
cerium (IV) compound such as cerric ammonium nitrate.
4. The process as claimed in claim 1 wherein the reaction is
o
conducted at a temperature in the range of 27-32 C, preferably at
o
30 C.
5. The process as claimed in claim 1 wherein the reaction is
carried out over a period of 20-30 hrs., preferably 24 hrs.
6. The process as claimed in claim 1 wherein the reaction is
conducted at atmospheric pressure.
7. The process as claimed in claim 1 wherein the reaction mixture
is purged with a gas such as nitrogen before addition of the
catalyst.
8. The process as claimed in claim 1 wherein the reaction mixture
is purged with a gas such as nitrogen for 10-30 mins., preferably
20 mins., after the addition of the catalyst.
9. The process as claimed in claim 1, wherein said amylopectin is
used in a proportion of 20 to 30 gms per 1.5 to 2.5 gms of
cerylamide not clear.
-3
10. The process as claimed in claim 1, wherein 1.5 :< 10 moles
of catalyst is used per 20 to 30 gms of amylopectin.
11. The process for the preparation of a graft copolymer for use
as a flocculating agent substantially as herein described and
il lust rated.

This invention relates to a process for the preparation of a graft copolymer for use as a flocculating agent comprising preparing a solution of the polysaccharide and adding acrylamide thereto with stirring, followed by addition of a catalyst solution thereto and allowing the reaction to continue, to obtain the graft copolymer.