Industrial polymers are
synthesized from simple compounds together in long chains. For a class of
natural or synthetic substances composed of very large molecules called
macromolecules that are multiples of simpler chemical units called monomers.
The polymers are many materials in living organisms, including for example
proteins, cellulose, and nucleic acids. They also form the basis of minerals
such as diamond, quartz and feldspar and such synthetic materials such as
concrete, glass, paper, plastic and rubber.
The polymer refers to any
number of monomer units. When the number of monomers is very large, the
compound is sometimes called a high polymer. Polymers are not limited to the
monomers of the same chemical composition or molecular weight and structure.
Some natural polymers consist of a single type of monomer. Most natural and
synthetic polymers, however, consist of two or more types of monomers. These
polymers are known as copolymers.
Organic polymers play a
crucial role in living organisms, providing the material and structural basis
by participating in processes essential for life. For example, the solid parts
of all plants are made of polymers. These include cellulose, lignin and resins
different. Cellulose is a polysaccharide, a polymer consisting of sugar
molecules. Lignin is a complex of three-dimensional polymer network. Wood
resins are polymers of hydrocarbons, simple isoprene. Another isoprene rubber
polymer is familiar.
Other important natural
polymers are proteins, which are polymers of amino acids and nucleic acids,
which are polymers of nucleotides, complex molecules composed of nitrogenous
bases, sugar and phosphoric acid. Nucleic acids carry genetic information in
the cell. Starch, an important source of food energy plant, natural polymers
are composed of glucose.
Many inorganic polymers are
also found in nature, including diamond and graphite. Both are composed of
carbon. In diamond, carbon atoms are joined in a three dimensional network that
gives the hardness of the material. In graphite, used as a lubricant and in
pencil "leads", the carbon atoms in the binding of planes that can
slide over the other.
Synthetic polymers are
produced in a variety of reactions. Many simple hydrocarbons such as ethylene
and propylene can be converted into polymers with the addition of a monomer
after the growing chain. Polyethylene, which is consist of repeating ethylene
monomers, in addition to the polymer. It can be up to 10,000 monomers joined
the long, spiral chains. Polyethylene is a crystalline, transparent, and the
thermoplastic material, which softens with heat. It 'used for coatings,
packaging, molded parts, and the manufacture of bottles and containers.
Polypropylene is also crystalline thermoplastics, but is harder than polyethylene.
The molecules can be obtained from 50000 200000 monomers. This compound was
used in the textile sector and to make the items printed.
In addition to other polymers
are polybutadiene, polyisoprene, and polychloroprene, which are all important
in the production of synthetic rubber. Some polymers such as polystyrene, are
glassy and transparent at room temperature, as well as a thermoplastic
material. Polystyrene can be colored any shade, and is used in the manufacture
of plastic toys and other objects.
If an atom of hydrogen in
ethylene is replaced by the atom of chlorine, vinyl chloride is produced. This
polymerizes to polyvinyl chloride (PVC), a colorless, hard, hard,
thermoplastic, which can be realized in various forms, such as foams, films and
fibers. Produced by the reaction of ethylene vinyl acetate and acetic acid,
polymerization is an amorphous, soft resins used in coatings and adhesives, and
copolymerizes of vinyl chloride for the production of a large family of
thermoplastic materials.
Many important polymers have
oxygen atoms or nitrogen, as well as carbon in the main chain. Among these
macromolecular materials with oxygen atoms are polyacetals. The easiest way is
polyformaldehyde polyacetal. It has a high melting point and is crystalline and
resistant to wear and the effect of solvents. Acetal resin is more like any
other metal and plastic used in the manufacture of machine parts such as gears
and bearings.
A linear polymer is
characterized by a repetition of the ester groups in the main chain is called a
polyester. Open-chain polyesters are colorless, crystalline materials,
thermoplastics. People with high molecular weight (10,000 to 15,000 molecules)
are used in the manufacture of films, moldings, and fibers such as Dacron.
Polyamides are of natural
origin and milk casein Zein, found in corn (maize), including plastics, fibers,
adhesives and coatings are made. Among the synthetic polyamide resins are
urea-formaldehyde, which are thermostable. Used to produce moldings and as
adhesives and coatings for textiles and paper. Equally important are the known
polyamide resins such as nylon. They are resistant to strong, heat and abrasion
resistant, fireproof and nontoxic and can be colored. Its best use is known as
a textile fiber, but they have many other applications.
Another important family of
synthetic organic polymers consists of linear tests urethane group.
Polyurethanes are used in the manufacture of elastomeric fibers known as the
base layer and spandex production and flexible and rigid foams.
Another class of polymers,
organic-inorganic mixed. The most important representatives of this family of
polymers are silicones. Its backbone consists of alternating silicon and oxygen
atoms with organic groups attached to each of the silicon atoms. Low molecular
weight silicones are oils and fats. High molecular weight species are versatile
materials that are soft rubber and elastic at low temperatures. They are also
relatively stable at high temperatures.
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