Inorganic and Hybrid Polymers as Evolution of Polymer Materials Science-Juniper Publishers
JUNIPER PUBLISHERS- Academic Journal of Polymer Science
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Nonmetallic materials, which are widely used, have
for the most part the polymer nature. These materials include
hydrocarbon polymers and inorganic high-molecular compounds that do not
contain hydrocarbon groups. Every class of polymers has a number of
advantages and disadvantages that requires specific problems to be
solved.
Inorganic polymers comprising up to 80% of the Earth’s crust involve mono elemental polymers (Cn, Sin, Gen, Pn, Bn, Asn, Sbn, Bin, Ten, Sen, Sn),
polyoxides, borides, nitrides, silicides, phosphides, carbides.
Polyoxides (silicates, phosphates, aluminates, borates, germanates,
titanates, complex polyoxides - clays, etc.) present the most widespread
class of inorganic polymers, which is of greatest interest from the
point of view of synthesis, properties, and the possibility of wide
application.
Inorganic polyoxides have a number of important
properties: incombustibility, high thermal and radiation stability, high
chemical activity, extremely low vapor pressure in the molten state,
environmental safety and raw materials availability. Low temperatures of
synthesis and processing as well as the solubility in water of some
polyoxides predetermine the possibility of polymerization under “mild”
conditions, chemical modification by hydrocarbons and co-processing with
organic polymers.
Another feature of inorganic polymers, particularly,
of some polyoxides is the presence of the planar structure, which is not
typical of organic and organometallic polymers, that implies the
properties different from those of linear and crosslinked polymers.
“Low-melting” oxides of various compositions with the predominant
content of one of the basic elements B, P, Sn, Pb, F, Bi, V, Mn are used
as oligomer compounds with Tsoft = 60-250 OC.
These oligomers, which are a new class of oligomers
and thermoplastics, are synthesized by solution and “extrusion” methods
at T = 25-250 °C and have Tsoft and Tflow like
those for organic polymers, which makes it possible to use the
traditional methods of synthesis, modification and processing of
plastics. On the basis of oligomers, thermal resistant polymers,
coatings,
adhesives and reinforced composites were obtained by heat treatment and
with the use of crosslinking agents. Mixtures of oligomer oxides with
organic polymers represent a new class of flame-retardant composites, in
which polyoxides can play the role of softening filler that makes it
possible to obtain high-filled composites, avoiding rheological problems
arising from their extrusion blending.
The possibility of obtaining polymer mixtures at
molecular and nano levels as well as fiber formation on casting is shown
accompanied by an increase in the strength of composites by a factor of
2 and in the Young’s modulus by a factor of 12. The effects of
orientation of boron polyoxide having a planar structure in the melt
flow in the presence of polyethylene accompanied by an anomalous change
in the rheological properties of the melts as well as fibrillation in
the region of the percolation ratios of the components were detected.
The incombustibility of polyoxides and low vapor pressure of polyoxide
melts allow one to use them for the development of non-combustible
materials that do not produce degradation products in fires that is
impossible when using organic polymers.
The high chemical activity of hydroxyl groups of
polyoxides not only allows their modification by organic compounds, but
also increases the thermal stability of some organic polymers
accompanied by a change in the reaction paths of polymer degradation
that allows one to consider them as high-temperature antioxidants.
Polyoxides contribute to low-temperature carbonization of
hydroxyl-containing polyhydrocarbons. An efficient method for
controlling the rate of polyoxide polycondensation as well as increasing
the hydrolytic stability of polymers and composites via addition of
nitrogen-containing compounds is proposed. With quantum chemical
calculations and computer simulation, the mechanism of the processes is
considered. The inorganic compositions have been developed that allow
the use of traditional technologies for materials molding: extrusion,
casting, pressing.
There is a huge human and material damage from
combustion of organic polymers, which is accompanied by the release of
harmful products of thermal degradation. Another significant drawback of
organic polymer products is a longterm
assimilation of their wastes in nature, which requires
considerable effort in their disposal and, finally, the need in
harmful organic solvents. It can be argued that materials based
on hybrid polymers and inorganic composites, the synthesis and
processing technologies of which are based on the use of water
are completely devoid of these shortcomings. It seems, it is high
time to return to the Stone Age.
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