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<p>Chemistry is a cutting edge science, and as cutting edge sciences go,
things tend to happen quite often. That's why we have the Current Topics
section of ChemWeb Online. It provides you with up to the minute cutting edge
chemistry news.</p>
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<center><h2>What is a Polymer?</h2></center>
<p>We are constantly exposed to polymer products in our everyday lives.
Our clothes are polymers, just as our plastic forks, insulating cups,
two liter plastic bottles, and plastic wrap are as well.
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<p>Some people believe that polymers are all man-made. These macromolecules,
as they are sometimes called, have been a part of the natural environment
since the beginning of life on earth. Polysaccharides, proteins, and nucleic
acids are polymers. Natural rubber is also a polymer. Polymer molecules make
up the structural, transport, protective, and reproductive systems of all
living things. Life processes rely on the chemical changes polymers
undergo as they are built up, broken down, or rearranged.
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<p>The term polymer comes from the Greek words polus and mer meaning many
parts. Polymers are huge molecules which are made up of repeating units
called monomers. The monomers may be identical or different. One single
polymer is often made up of thousands of monomers linked together.
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<p>One of the simplest man-made polymers is polyethylene, which is made
into clear fruit and vegetable bags. Polyethylene is formed by the
covalent bonding of many monomers of ethylene molecules. A typical
polyethylene molecule may have about 25,000 carbon atoms in its chain
and have a molecular weight of 350,000.
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<p>The number of monomers that join to form the final long chain is
theoretically infinite. But usually the number of monomer units falls in
the range of 1,000 to 10,000. Molecular weights range from 14,000 to 500,000.
It may come as a surprise to realize that a bowling ball or a tire can be
considered a single giant molecule due to cross-linkages that bond together
all the separate molecules into a giant network. The bowling ball may have
a molecular weight of about 1028 with a tire's molecular weight being even
larger.
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<p>Another important way of categorizing polymers is by their behavior
upon being heated. Thermoplastics melt and soften when heated. An example
of this would be the melting of a polyethylene bag, or the fusing of polyester
or nylon fabrics when a hot iron was used. The melting occurs because
individual molecules are not chemically bonded to each other. Held together
by van der Waals forces, polyethylene melts in the 110 -130 degrees Celcius
range. Nylon, held together by hydrogen bonds as well as by van der Waals
forces, melts at 265 degrees Celcius.
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<center><h2>A List of Common Polymer Products</h2></center>
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<ul>
<li>garbage bags
<li>insulated foam cups
<li>milk jugs
<li>toothpaste tubes
<li>sandwich bags
<li>fast food containers
<li>shoe strings
<li>junk food bags
<li>2-liter pop bottles
<li>motor oil bottles
<li>plastic knives forks and spoons
<li>shampoo bottles
<li>shoe string tips
<li>food wraps
<li>disposable razors
<li>egg cartons
<li>thread spools
<li>margarine tubs
<li>disposable diapers
<li>coffee stirrers
<li>insulation caulking
<li>beverage boxes
<li>shrink wrap
<li>bubble pack
<li>Silly String
<li>Silly Putty
<li>Slime
<li>cellophane tape
<li>epoxy glue
<li>Super Glue
<li>dish pan
<li>pens
<li>plastic glasses and cups
<li>plastic dishes
<li>Teflon cookware
<li>food storage containers
<li>comb
<li>toothbrush
<li>ceiling light covers
<li>table tops
<li>chair seat
<li>carpet
<li>refrigerator
<li>telephone
<li>floor tile
<li>synthetic fabrics for clothing
<li>rubber soles on shoes
<li>bicycle and automobile paint
<li>bicycle and automobile tires
<li>windshield
<li>dashboard
<li>floor mat
<li>vinyl top
<li>bicycle hand grips
<li>reflector
<li>shoe box
<li>vinyl wall covering
<li>sunglasses glasses
<li>compacts
<li>contact lenses
<li>pencil cases
<li>lipstick tubes
<li>chapstick tube
<li>hair spray
<li>windbreaker
<li>raincoat
<li> hose
<li>galoshes
<li>umbrella
<li>rubber gloves
<li>sweater
<li>Nerf ball
<li>Frisbee
<li>snorkel
<li>swim fins
<li>wet suit
<li>volleyball and net
<li>basketball
<li>racquetball
<li>tennis ball
<li>tennis racquet and strings
<li>guitar strings
<li>balloons
<li>rubber band
<li>credit card
<li>portable radio
<li>computers
<li>watch faces
<li>safety glasses
<li>false teeth
<li>hearing aids
<li>lunch box
<li>coffee mug
<li>thermos bottle
<li>lunch tray
<li>flower pot
<li>supermarket meat trays
<li>microwave cookware
<li>lawn chair
<li>welcome mat
<li>Astroturf
<li>Velcro
<li>football helmet
<li>football
<li>pads
<li>cleats
<li>football
<li>shuttlecock
<li>hockey puck
<li>buttons
<li>erasers
<li>thread
<li>wig
<li>false eyelashes
<li>surfboards
<li>parachute
<li>sailboat
<li>sail
<li>Pontiac Fiero
<li>Corvette
<li>Honda CRX
<li>gears
<li>Lucite sculpture
<li>playing cards
<li>floor wax
<li>furniture polish
<li>sousaphone
<li>clarinet
<li>flute
<li>recorder
<li>records
<li>tape recorder
<li>videotapes
<li>audio tapes
<li>computer discs
<li>luggagetypewriter case
<li>typewriter ribbon
<li>metallic balloon
<li>Habitrail
<li>flea collar
<li>index tabs
<li>life raft
<li>model plane
<li>model car jewelry
<li>pacifier
<li>baby bottles
<li>baby rattles
<li>cushions
<li>foam rubber pillow
<li>pillow case
<li>exercise mat
<li>photographic film
<li>photographs
<li>flashcubes
<li>decorative fruit
<li>plastic flowers
<li>mannequins
<li>street signs
<li>store signs
<li>book bag
<li>chemistry classroom desk
<li>school desk
<li>knapsack
</ul>
<p>That's a lot of stuff don't you think?
<p>Heard about any news in chemistry? Let us know, go to the <br>
<a href="../../gather/chemnews.htm" target="_top">
<h2>Chemistry News Page</h2></a>
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