:: polymers

by Sean

A polymer is a type of molecule with a large molar mass that consists of many repeating subunits called monomers. These monomers are held together by polar covalent bonds. Well known examples of polymers include plastics, DNA and proteins. The popular term polymer is widely associated with plastic; polymers do encompass a large amount of the natural and synthetic materials that have varying properties and uses.

Addition Polymerization Process

1 – Initiation: A molecule is initiated using peroxide with an unpaired electron to the double bond of the carbon atom. This creates a double bond at the end of the molecule.

2 – Propagation: This trend continues and the chain propagates.

3 – Termination: When any unpaired electron ends forming a covalent bond that links the chain together.

Here is a video of the process:

Properties

-Polymers are used in plastics mainly as containers because they are very stable and unreactive.

-Generally they are flexible especially when they are heated.

-Held together by Vander Waals forces because of the large amount of carbon atoms in polymers.

Crosslinking

Crosslinking occurs between two different chains of polymers. They attach by bonding together. This creates very strong polymer compounds. These become much more rigid.

Natural Polyamides

These polymers are the naturally forming ones and are commonly known as amino acids, proteins, carbohydrates, starch and sugars. These polymers can take different structures. The four main formations are primary, secondary, tertiary and quaternary.

This is a primary amino acid.

Nucleic Acids

These acids are known as deoxyribonucleic acid (DNA). This polynucleotide is the base of all life. It contains the codes which creates the proteins which define who and what we are. The DNA strands are formed from a pair strands made up of four different nucleotide monomers. They are: adenine, thymine, guanine and cytosine.

Fats and Oils

Fats and oils are mainly liquid which polymers of fatty acids (carboxylic acids) are. These can either be saturated or unsaturated.  They are insoluble in water due to the non polar nature of the molecules.