Реферат на тему Polymers Essay Research Paper Polymers are large
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Polymers Essay, Research Paper
Polymers are large molecules
composed of smaller molecules called monomers.
Monomers are produced and either grow together
or are assembled to produce a single polymer.
There are synthetic and natural polymers. Some
examples of natural polymers would be wood,
starches, fingernails, and hair. Synthetic polymers
are usually referred to as plastics. Petroleum, is the
primary monomer used to produce polymers. An
English chemist named Alexander Parkes was the
first scientist to produce the first synthetic polymer
in 1862. John Wesley Hyatt, an American, was
the first person to produce a useable polymer two
years later. He named the product celluloid. The
prime virtue of polymers is a high
strength-to-weight ratio. Industrial-strength
polymers surpass titanium in tensile strength. To
add strength and improve flexibility, polymers are
sometimes fortified with short-fiber additives,
mostly fiberglass. This is known as a polymer
composite. One particular polymer has three times
the strength of tempered steel and is being used in
bullet proof vests. Another composite will be used
to fasten together the sections proposed space
stations. Polymers have also been used in cars,
including the Chevrolet Camaro and the Pontiac
Fiero. New polymers are being created with more
strength and flexibility by combing two chemically
different polymers and producing a block
copolymer. Combinations of block copolymers
and composites and intended for use in booster
rockets and in materials of Earth-orbiting
installations. Most common polymers are usually
solid, but a new class of polymers is being
introduced in a liquid crystal state. Although these
polymers still have the physical characteristics of
liquid, they are structured more like solids. Many
liquid crystals are transparent at one temperature
and colored at another temperature. This makes
them suitable for use in liquid crystal displays, such
as in digital watches, hand-held calculators, and
lap-top computers. A new liquid polymer,
consisting of a mixture of iron and nickel, is being
used to make metal links that can be used in
paper, glass, and on electronic circuit boards.
Despite the development and widespread use of
polymers, scientific understanding is still sketchy.
Polymer development has occurred through trial
and error. Scientific shortcomings are becoming
more apparent in the search for polymers that can
meet the demands for high technology of today.
The new study is on the microstructure of
polymers while still in a liquid state. The purpose is
to learn how the solid-state structure is developed.
The ultimate goal is to be able to predict
properties from a specific material under a
constant set of processing conditions.