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Methods of producing organic-inorganic hydrogels are divided into
groups.
1. Mixture of inorganic additives in the form of nano - to microparticles or
soluble polymer, or a solution of monomers c their subsequent polymerization.
Usually, the covalent crosslinking of the polymer system is required, because the
inorganic particles serve as the centers of physical crosslinks.
2. The inorganic phase as a result of formation of the sol - gel - a process
which provides for the introduction of the monomer or polymer solution, the
inorganic component precursor and its subsequent conversion to the various
chemical reactions in the solid water - insoluble particles. The final stage of the
polymerization of monomers, if required, crosslinking. When implementing the
sol - gel - phase technology inorganic precursor may be introduced into the final
polymer hydrogel by diffusion. Example - obtaining hydrogel polymer filled
with particles of silica into the reaction system tetra alkoxy silanes, their
hydrolysis and subsequent condensation of the silanol groups. On its face, this
group of processes include the synthesis of polymeric hydrogels containing
metal particles. In these processes, a hydrogel polymer solution is introduced
inorganic salt which is reduced to form the free metal.
Im p roved m echan ica l properties o f the po lym e r hydrogels.
One of the
disadvantages of polymer hydrogels with high water content - their low strength
properties. The introduction of hydrogel inorganic phase in some cases to solve
the problem. In [122] gave obtaining organic-inorganic supersorbents
copolymerizing acrylic acid and acryloyl oxy ethyl trimethylammonium chloride
in an aqueous medium containing particles morillonita repairs. What - or
crosslinking additives in copolymerization is not injected. Gelation occurred as a
result of interaction of positively charged units acryloyl oxy ethyl trimethyl
ammonium chloride and montmorillonite. The strength of the hydrogel
composition is 13 times higher compared with the same hydrogel without
containing montmorillonite. The increase in the modulus of elasticity in the
amplification of the hydrogel montmorillonite noted for polyacrylamide
hydrogel [123]. A significant improvement in the mechanical properties of the
hydrogel covalently of non-crosslinked copolymer HEMA-monometakrilovy
ether PEO-IAC revealed the introduction of attapulgite nanoparticles (mixed
magnesium aluminum silicate), which serves as a center of physical cross
linking of the copolymer [124]. Examples of the synthesis was performed by
copolymerization of the monomers in water containing a dispersion of mineral
particles. Improved mechanical properties, achieved while increasing the water
content of the obtained hydrogel as compared with the same hydrogel without
covalently crosslinked inorganic component.
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