Organic Chemistry
Chapter 10.5 Polymerization
Polymerization is the taking of small molecules, called monomers such as ethene, and combining them in very long chains called polymers. These polymers are the family in which plastics fit. There are both synthetic and natural polymers.
Natural polymers include, rubbers, amber, wool, silk and Synthetic polymers include plastics such as nylon, polyethylene, and Styrofoam.
We saw some examples of polymerization when we looked at ethane and ethane. These are called addition polymers.
There are other examples such as polyvinyl chloride
Or polypropene
Practice Page 448 #1,3,7
Condensation polymerization is when two different monomer molecules combine into a larger polymer chain, “condensing” out a smaller molecule such as H2O, NH3, or HCl. This happens in many natural and synthetic polymers such as DNA, proteins, polyester, cellulose and starches. 3 types of condensation polymerization include:
- Polyesters (butter)
- Polyamides (proteins and nylon)
- Polysaccharides (starch and cellulose)
- Lipids and Polyesters:
Lipids are formed in esterification reactions of glycerol and fatty acids (long chain carboxylic acids).
Polyesters are formed when water is created in an esterification reaction and the two esters subsequently attach. This process is repeated to form long ester chains. This usually occurs where the carboxylic acid has two carboxyl groups (COOH) and the alcohol has two hydroxyl (OH) groups
- Proteins and Nylon
Proteins are formed by amino acids in reactions much like esterification, but rather than a carboxyl group attaching to an OH group, the OH group is replaced with a NH2 group which is attached to the carboxyl group of an amino acid. This polymer is called a polypeptide. The linkage is called an amide linkage.
In nylon, the polymer chains line up to attaches parallel to each other using strong hydrogen bonds. Kevlar is a similar material used in bullet proof vests due to the strong connections between polymer chains.
- Starch and Cellulose (polysaccharides)
Starch, due to the cyclical formation of its polymers creates a strong material for structure. Cellulose, due to the long straight chain of it polymers is good for energy.
Glucose and Glucose (simple sugars) attach together to make the repeating base structure for polysaccharides such as starch and cellulose, as well as water molecules
Practice: Page 460 #1,2,4,7,11,14