What is polymer?

Polymers are made up of many many molecules all strung together to form really long chains (and sometimes more complicated structures, too). This is a polymer. What makes polymers so fun is that how they act depends on what kinds of molecules they're made up of and how they're put together. The properties of anything made out of polymers really reflect what's going on at the molecular level. So, things that are made of polymers look, feel, and act depending on how their atoms and molecules are connected, as well as which ones we use to begin with! Some are rubbery, like a bouncy ball, some are sticky and gooey, and some are hard and tough, like a skateboard.

Poly- means "many" and -mer means "part" or "segment". Mono means "one". So, monomers are molecules that can join together to make a long polymer chain. 

This is a simple diagram of a chain of monomers.

Sometimes polymers are called "macromolecules". "Macro" means "large" and by now you've figured out that polymers must be very large molecules!

Most of the polymers we'll talk about here are linear polymers. A linear polymer is made up of one molecule after another, hooked together in a long chain. 

Now, linear polymers don't have to be in a straight, rigid line. Those single bonds between atoms in the backbone can swivel around a bit.

To the rest of the world, "linear" means "straight and not curved" but for polymers, linear means "straight and not branched".

          This is a linear polymer!              

                                                            This is a branched polymer!

Polymers Are Like TV: Both Have Lots and Lots of Repeats

The atoms that make up the backbone of a polymer chain come in a regular order, and this order repeats itself all along the length of the polymer chain. (Boy, that makes sense, doesn't it - given that polymers are made by hooking up one molecule after another after another after another.....)

For example, look at polypropylene (sounds like polly-pro-pill-een):

Its backbone chain is made up of just two carbon atoms repeated over and over again. One carbon atom has two hydrogen atoms attached to it, and the other carbon atom has one hydrogen atom and one pendant methyl group (CH₃). 

To make things simple, we usually only draw one unit of the repeat structure, like this:

The repeat unit is put inside brackets, and the subscript n just stands for the number of repeat units in the polymer chain.

Another example: styrene monomers join together to make polystyrene:

 

There are a lot of example of polymer. Example include nylon, acrylic, PVC, polycarbonate , cellulose, and polyethylene!