Explanation:
monomer
smaller molecules that are used to prepare a polymer.
may or may not be equivalent to the repeat unit.
oligomer
a molecule consisting of several repeat units of a monomer, but not large enough to be considered a polymer
polymers
arge, usually chainlike molecules that are built from small molecules called monomers. Polymers form the basis for synthetic fibers, rubbers, and plastics and have played a leading role in the revolution that has been brought about in daily life by chemistry.
first synthetic polymers were produced as
by-products of various organic reactions and were regarded as unwanted contaminants.
first completely synthetic plastic
Bakelite, a substance that when molded to a certain shape under high pressure and temperature cannot be softened again or dissolved. Bakelite is a thermoset polymer. In contrast, cellulose nitrate is a thermoplastic polymer; that is, it can be remelted after it has been molded.
ethylene
basic raw material in the production of polyethylene and other important compounds. Over 135 million tons of ethylene were produced worldwide in 2010 for use in the polymer, petrochemical, and plastic industries. Ethylene is produced industrially in a process called cracking, in which the long hydrocarbon chains in a petroleum mixture are broken into smaller molecules.
monomer ethylene (C2H4) is
a gas at room temperature, but when polymerized, using a transition metal catalyst, it is transformed into a solid material made up of long chains of -CH2- units called polyethylene. Polyethylene is a commodity plastic used primarily for packaging (bags and films).
nylon
the silky appearance and strength of this thread and realized that nylon could be drawn into useful fibers.
The reason for this behavior of nylon is now understood. When nylon is first formed, the individual polymer chains are oriented randomly, like cooked spaghetti, and the sub- stance is highly amorphous. However, when drawn out into a thread, the chains tend to line up (the nylon becomes more crystalline), which leads to increased hydrogen bonding between adjacent chains. This increase in crystallinity, along with the resulting increase in hydrogen-bonding interactions, leads to strong fibers and thus to a highly useful mate- rial. Commercially, nylon is produced by forcing the raw material through a spinneret, a plate containing small holes, which forces the polymer chains to line up.
polyethylene
simplest and one of the best-known polymers, constructed from ethylene monomers.
CH2=CH2
Polyethylene is a member of one subset of synthetic polymers classified as plastics.
properties of polyethylene
Polyethylene is a tough, flexible plastic used for piping, bottles, electrical insulation, packaging films, garbage bags, and many other purposes.
Its properties can be varied by using substituted ethylene monomers. For example, when tetrafluoroethylene is the monomer, the polymer Teflon.