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polar groups, which creates new control possibilities compositional properties of
hydrogels. The composition of the hydrophilic polymer may include units
hydrophobic monomers. In such cases, composite hydrogels play a role and
hydrophobic interactions.
When considering the hydrogels formed from hydrophilic polymers, their
biphasic nature is not always evident. For example, in the interpolymer
complexes can be expected to combine polymers at the molecular level and the
formation of single-phase polymer systems. To prove the bi-phase structure of
composite hydrogels used a variety of physical methods such as electron
microscopy, atomic force microscopy, the various options calorimetry and
thermomechanical analysis, small angle neutron scattering and X-rays.
Especially the last two promising method, allowing to study the material
structure in the hydrated state, under conditions where the polymer system is
present in the solvent (water), contributing to the reconciliation of polymers. The
hydrogel was tested in a state of nature; necessarily presuppose the existence in
these polymeric systems, at least two types of macromolecules and water.
The hydrophilic polymers used for the production of composite hydrogels
are numerous, varied, but extends to:
- Hydroxyl-containing polymers - PVA, polymers and copolymers of 2 -
hydroxyethyl methacrylate;
- Polyethers - PEO block - copolymers of ethylene oxide and propylene
oxide;
- Polymers having amide groups - polyacrylamide (PAA), poly-N,N-
dimethylacrylamide,
poly-N-isopropylacrylamide
(PIP),
poly-N-
vinylpyrrolidone (PVP);
- Ionic polymers containing acid groups - polymers and copolymers of
acrylic and methacrylic acids, unsaturated sulfonic acids;
- Poly dimethylamino ethyl methacrylate, polyvinyl, etc..
Also used synthetic polymers and natural origin. They must first polymers
include proteinaceous nature (gelatin) and polysaccharides. These may be
nonionic polymers (hydroxy derivatives of cellulose, dextran) or ionic (anionic-
carboxy derivatives of cellulose and dextran, carrageenan, cationic-chitosan).
For composite hydrogels based on hydrophilic polymers can be used
almost all of the known methods, from overlapping finished polymer in solution
and its binding as a result of various physical and chemical interactions, and to
the synthesis of polymers from monomeric compounds to form a unit - and graft
copolymers, and interpenetrating polymer networks (UPU).
Composite hydrogels based on interpolymer complexes
in aqueous
solutions are capable of forming hydrogen bonds, they are characterized by ionic
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