Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 10, pp. 1898−1901.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
O.V. Suberlyak, Yu.Ya. Mel’nik, N.M. Baran, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 10, pp. 1746−1749.
AND POLYMERIC MATERIALS
Formation of Membranes from Aliphatic
O. V. Suberlyak, Yu. Ya. Mel’nik, and N. M. Baran
L’vivs’ka Politekhnika National University, Lviv, Ukraine
Received November 27, 2008
Abstract—The performance of polyacrylic acid of various molecular weights and of its formulations with sodium
tripolyphosphate and Na2EDTA as inhibitors of deposit formation and as dispersants was examined..
The development of novel ﬁ ltering, in particular,
membrane, materials with special properties is a topical
problem . Particular attention should be given to the
use of polymeric materials for preparing membranes for
medical purposes, in particular, for dialysis .
It is known that aliphatic polyamides are highly
resistant to alkalis and to the majority of solvents, and
membranes based on them exhibit selective retaining
power in baromembrane processes and preserve
physicomechanical properties in a wide temperature range
(up to 130°C) . At the same time, in dialysis, which
is widely used in medical practice, e.g., in hemodialysis,
polyamide membranes are unsuitable because of their
low dialytic permeability.
A promising way to increase the dialytic permeability
of polyamide membranes is their modification, in
particular, physical modiﬁ cation by blending the initial
aliphatic polyamides under the conditions of their viscous-
ﬂ ow state or in solution with a modiﬁ er that increases the
permeability, so as to preserve high physicomechanical
properties of membranes. As a modifier we chose
amphiphilic low-molecular-weight polyvinylpyrrolidone,
which has found use in medical practice as a sorbent
thanks to its nontoxicity, high hydrophilicity, and
tendency to complexation with both electron donors and
Among industrial processes for production of ﬁ lm
membranes, the most widely used is membrane forming
from polymer solutions. Dissolution of polymers with
the aim to prepare the initial working solutions for ﬁ lm
formation is an important step of polymer processing,
determining the supramolecular structure of the polymer
in the ﬁ lm owing to physical interaction of components
in solution. The choice of the working solution
concentration depends on the kind of the polymer, its
molecular weight, and solvent used and determines the
ﬁ lm formation conditions. One of the main limiting
parameters governing the choice of the working solution
concentration is its viscosity .
The goal of this study is the development of
a procedure for forming membranes based on aliphatic
polyamide–polyvinylpyrrolidone blends from solutions
in formic acid and to determine the optimal compositions
of forming solutions for preparing functionalized highly
hydrophilic dialysis membranes.
In our study we used poly-ε-caproamide (PA-6) with
MFI = 8.67 g/10 min, copoly(hexamethyleneadipamide
–caproamide) (PA-66/6) with MFI = 12.0 g/10 min, and
polyvinylpyrrolidone (PVP) with MW = 12 000 ± 2000.
Blending of PA and PVP was performed in solution in
the course of polymer dissolution for preparing casting
solutions, or in a melt by vigorous dispersion in a worm
plasticizer at 230°C, with the formation of a uniform
polymer blend by dissolution of PVP in the polyamide
melt. The blends contained from 1 to 10 wt % PVP.
Membranes were formed by casting solutions of
PA–PVP blends in formic acid containing a deﬁ nite