POLYMERS POLYMERS, (a more acceptable term than plastics”) The one area of chemistry in which this country leads the rest of the world.

poly = many meros = parts, units then, polymer = many parts monomer > p-o-l-y-m-e-r

The first “recorded” polymer: Klatte didn’t know what he had... but he wrote it up in his lab notebook!

Some terms to remember: Addition (chain growth) polymer Condensation (step growth) polymer Thermoplastic polymer Thermosetting polymer Syndiotactic polymer Isotactic polymer Atactic polymer Co-polymers

ADDITION POLYMERS also called “chain growth” polymers ADDITION POLYMERS also called “chain growth” polymers All parts of the monomer are retained in the polymer. Nothing is lost.

The monomers simply join to each other. – something like this:

Some Some well-known addition polymers:

Additional “Addition” polymers Note the two groups on the vinyl carbon...

Note the position of the substituent on the vinyl carbon...

Ways to catalyze polymerization:

A Radical has an “odd” or “unpaired” electron, but NO CHARGE... Electrons pair to either side, forming covalent bonds.

ANION (negatively charged) catalysts. Anions “push” the negative electron pairs ahead.

CATION (positively charged) catalysts. Cations “pull” negatively charged electron pairs toward themselves.

CONDENSATION POLYMERS also called “step growth” polymers Small molecules are lost between units.

POLYAMIDES

Nylon 6,6 and Nylon 6

“NYLON ROPE” The “NYLON ROPE” trick...

POLYESTERS

DACRON DACRON, a polyester We are grateful for wrinkle-free fabrics; -- no starching; no ironing!

KODEL KODEL, another polyester Used to make fabric, tire cord; Mylar film in magnetic recording tape. Aluminized Mylar in Echo satellite, a giant reflector orbiting the earth.

So far, what you have seen are linear polymers; the product of two-point chain growth. Linear polymers are usually “thermoplastic” polymers. They soften with heat, and can be “re-molded” if the product is not perfect.

Three-point chain growth gives rise to cross-linked polymers. These are usually “thermosetting” polymers. They do NOT soften with heat. If the final product is not perfect, it goes into the scrap pile.

1,3-butadienes can undergo 1,4 addition..leaving a double bond for cross-linking.

COPOLYMERS COPOLYMERS consist of polymerizing together two or more different monomers The monomers need not be alternating, but may be combined in various configurations.

Some other interesting polymers: A tough ABS polymer Glyptal resin Polycarbonates Polyurethanes

Three different monomers in an interesting co-polymer. An extremely durable high-impact polymer: NFL helmets, pads, TV & radio chassis, etc.

Glycerol offers THREE points for chain-growth; leading to a cross- linked polymer Glyptal resin makes a strong, solid polymer matrix for electronic parts. It has remarkable strength and rigidity.

A “transesterification” with an ester of a “hypothetical acid”. Many “clear, colorless” soft drink bottles are polycarbonates.

Urethane, another ester of a “hypothetical acid”. Alcohols and phenols react with isocyanates, yielding “urethanes”.

Again, each reactant has 2-point chain growth Volatile materials (Freon 11) added produce bubbles, yielding polyurethane foam. Glycerol can give cross-linking. Bisphenol A gives a different polyurethane.

Phenolformaldehyde Phenol reacts with formaldehyde in dilute base... to give hydroxymethyl groups in the 2 -, the 4- and the 6 – positions...

Further condensation leads to a cross linked polymer... Bakelite known as Bakelite, one of the oldest commercial plastics

2,4,6-triamino-S-triazine undergoes a similar reaction with formaldehyde. The polymer: “Melmac” was the early “cafeteria dishware”.

An interesting research possibility: Then, why not with amines, also...

An interesting “cyclization” reaction:... taken from an early Hiskey & Jung (or Jung & Hiskey) publication in the JACS...

... leading to additional research possibilies... Since pABA cannot “back-bite”, the chain must grow linearly...

Quick review: you should know: Addition (chain-growth) Polymer Condensation (step-growth) Polymer Thermoplastic Polymer Thermosetting Polymer Isotactic Polymer Syndiotactic Polymer Atactic Polymer Co-polymer