11 Polymers

"Poly" comes from the ancient Greek πολύ, polý and means "many". "Mer" also comes from the ancient Greek μέρος, méros and means "part". Accordingly, a polymer is a chemical which consists of macromolecules, that is to say of several repeating units.

Wood consists of the biopolymers cellulose, hemicellulose and lignin. Plastic bottles are made of synthetic polymer: polyethylene terephthalate. Salt, on the other hand, is a chemical compound which consists of positively charged ions (Na+) and negatively charged ions (Cl-). These ions form an ion lattice of a particular crystal structure.

Sodium polyacrylate is a super absorber capable of absorbing 100 to 1000 times its mass of water. What is interesting is that this ability decreases drastically with the salt content of the water, as the salt competes with the water.

polyacrylate

Order the following polymers according to their production rate (from highest to lowest):

1. polypropylene (PP) 2. Polyvinyl chloride (PVC) 3. polyethylene (PE)

1-2-3

3-2-1

3-1-2

Of the world’s plastic production, polyethylene makes up for 36%, polypropylene 21% and polyvinyl chloride 12%. Polyethylene is mainly used in the packaging industry: plastic bags, transparent film, plastic bottles. Polypropylene is used in the interior fittings of passenger cars, is spun into textiles and is used in the food industry for thicker packaging such as yogurt cups or drinking straws. Polyvinyl chloride is used in the manufacture of pipes, floor coverings, cable sheaths and for music records.

Hair consist mainly of keratin, which is also found in fingernails, claws and horns. The amino acids of the keratin form a α-helix, two such α-helices form a super helix and two of these form so-called protofibrils etc. Disulfide bonds can form between the amino acids, the more these bridges are present, the stiffer the fiber. These disulfide bridges are broken during a hair perm and are subsequently re-formed.

Styropor is a large-pore expanded polystyrene foam. If the Styropor cup is dipped in acetone, the polystyrene dissolves and the enclosed air is set free, which becomes visible in the form of bubbles.

aceton2

Styropor is a large-pore expanded polystyrene foam. If the Styropor cup is dipped in acetone, the polystyrene dissolves and the enclosed air is set free, which becomes visible in the form of bubbles.

aceton2

Wallace Carothers was an American chemist (born in 1896, died in 1937), employed by Dupont. He developed the synthesis for polyhexamethylene dipamide (nylon) in 1935, which was the first fully synthesized fiber.

wallace

The polymer, which is located in the hair gel, mostly polyvinylpyrrolidone, binds water, whereby the gel is gel-like. Add salt, which consists of sodium and chloride ions, and these ions take the place of the water, water is released, and the gel liquefies.

Gel-NaCl-2

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1 freepik.com

2 chemgapedia.de

3 Luxembourg Science Center

4 Luxembourg Science Center

5 commons.wikimedia.org

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8 Luxembourg Science Center

9 Luxembourg Science Center