Properties of Destructively Modified Flocculants
T. V. Shevchenko, Yu. V. Ustinova, E. V. Ul’rikh, and V. P. Amelenko
Kemerovo Technological Institute of Food Industry, Kemerovo, Russia
Received April 8, 2009
Abstract―The destructive modification of Magnaflok-919 high-anion polyacrylamide under the action of a
microwave irradiation was studied. As a result a new, more effective flocculant was obtained, which allows
valuable alimentary components (protein and edible fat) to be completely extracted from milk industry sewage.
ISSN 1070-4272, Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 3, pp. 522–524. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © T.V. Shevchenko, Yu.V. Ustinova, E.V. Ul’rikh, V.P. Amelenko, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 3,
At present polyelectrolytes based on polyac-
rylamide (PAA) are widely used in various industries
for stabilization or destruction of colloid systems [1, 2].
It was found experimentally that molecular weight
(MW) of macromolecules is the crucial characteristic
of polyelectrolytes. In this connection a necessity
arises to develop reliable, accessible, and fast methods
of directional adjustment of MW of polymers, one of
which is the modification under the action of chemical,
physicochemical, and physical factors.
Chemical modification by low-molecular bifunc-
tional compounds resulting in an appreciable increase
in the molecular weigh of polyelectrolytes [3–5] has
been most studied. The modification under the in-
fluence of physical actions, in particular of a micro-
wave irradiation (MWI), is developed to a lesser
extent, though it accelerates the destruction of poly-
mers and the development of chains with the formation
of spatial structures.
In the present work the microwave PAA modifica-
tion was carried out with the aim to change the
structure of the main mass of macromolecules due to
the radicals formed upon the destruction of a certain
part of initial macromolecules.
In the work we used an aqueous solution (weight
fraction of 0.5%) of a high-molecular (M = 30×
a.w.u.) anionic PAA flocculant (Magnaflok-919,
М-919) with an ionogenity degree of 70% containing
three types of units in the macromolecule (carboxylic,
carboxylate, and amide groups).
A flocculant solution of volume 100 ml was subject-
ted to irradiation in a reaction chamber of a SAMSUNG
household microwave with a power output of 100 W
and frequency of 2.45 GHz (25 vibrations per 1 s). The
effect of irradiation time on the MW of flocculant
macromolecules was determined by viscosimetry. The
kinematic viscosity was measured with an Ubbelohde
capillary viscosimeter, the characteristic viscosity was
calculated from these data by standard procedures.
It follows from the figure that the kinematic vis-
cosity varies along a complicated trajectory: originally
it increases up to a certain limit (12 s is the optimal
irradiation time) and then decreases. In the stage of its
increasing the MW of a polyelectrolyte increases as a
result of postpolymerization due to radicals created
upon the irradiation, the modification process pre-
vailing over the destruction process.
Physicochemical properties of the destruction pro-
ducts were determined by viscosimetry, their storage
stability was also studied.
To determine molecular weight, we used the Mark–
[η] = KM
Here [η] is the characteristic viscosity found gra-
phically; K and α are constants, K characterizes a
specified polymer type in a specified solvent, α is
defined by the shape and flexibility of macromolecules
in the solution.
For the PAA solution in water these constants are:
K = 0.63×10
, α = 0.8 . The calculated data are
presented in Table 1.