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Hydrogels formed from the AMS, the group can be identified: hydrogels
based nonionic polymers; Hydrogels, wherein one of the polymers is ionic;
hydrogels comprising two ionic polymer of opposite charge macromolecules.
Clearly in these groups besides hydrogels effects due to entanglements of the
macromolecules may be other types of interactions between macromolecules:
hydrogen bonding, hydrophobic interactions, iondipolnye interactions, typical of
polyelectrolyte systems. Character interactions in composite hydrogels affect
their properties.
A typical example of non-ionic hydrogels are a composite or poluVPS
AMS, formed from acrylamide polymer and IPA [35, 36], which is used to
produce heat-sensitive membrane using PIP ability to collapse at a temperature
above the lower critical solution temperature of the polymer (32-34 °C). The
character of the temperature effect in the composite hydrogel depends on the
method of its production. In [35] describes the production of membranes based
VLCP. First of PAA mesh formed by radical copolymerization of acrylamide
and a crosslinking monomer - MBAA in an aqueous medium in the presence of
sodium persulfate and N, N, N ', N'_tetrametiletilendiamina. Then, the hydrogel
cross-linked PAA introduced IPA without the finisher and spent his
polymerization under the influence of sodium persulfateя.
We have found that when the temperature increases above 32 °C increases
the permeability of the membrane with respect to certain water-soluble organic
substances, and is explained as follows. If the lower critical solution temperature
PIPA collapses, but since sufficiently strong mesh holds PAA hydrogel structure
and volume, it causes the compression phase PIP formation in the membrane
pores, and increases its permeability. In [36] the membrane of the same
components and in the same sequence of polymerization processes exhibit the
opposite effect, that is, when the temperature rises permeability decreased. The
differences are due to other conditions for obtaining the composite hydrogel. In -
the first, instead of the floor - AMS AMS was formed (in both stages use
stapler). In - the second, a second stage (polymerization IPA) was performed by
UV - irradiation, resulting in a nonuniform distribution of polymer components
in the membrane. The inner layers have been enriched IPA polymer that
contracts when the temperature increases and partially dehydrated, which
reduced the permeability of the membrane. These two examples demonstrate a
wide range of applications IPN synthesis method, thus providing a composite
hydrogels diametrically opposite properties from the same monomeric raw
material.
Known simple method of producing heat-sensitive hydrogels based on
simultaneous IPN hydroxyethyl - PAA [37]. In the synthesis of such IPN
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