Polymers

Polymers – very large molecules made when hundreds of monomers join together to form long chains. They have no double bonds.

Synthetic Polymers (Plastics) – man-made polymers

 

Monomers – a molecule that can be bonded to other identical molecules to form a polymer. Polymerisation – the combining of monomers to form polymers

Addition Polymers – the monomer is thousands of the same alkene molecules, whose double bond is broken to join the molecules together in one long chain e.g.

 

If you had n (number) of this monomer:

Then n of the monomers would join together, by breaking the double bond and connecting to the other monomers to form a long chain:

This would then be written as a repeated unit:

Condensation Polymers – a polymer formed by a condensation reaction (one in which water is given out).

Artificial Polymers – where a product is formed from two different types of monomers arranged alternately and linked together. In this case the monomers usually contain a minimum of two of the same/different functional groups at the end of their molecules. When the polymer forms, a small molecule such as H2O or HCl is lost at each junction. Artificial polymers include:

• Ester Linkage – a polymer found between di-carboxylic acids and a diols. (-COO-) g. Terylene

• Amide Linkage – a polymer formed between di-carboxylic acids and diamines (-CONH-) g. Nylon

Natural Polymers – those polymers found in nature and are usually condensation polymers

• Peptide (Amide) Linkage – a protein (polypeptide) formed between amino acid molecules

• Polysaccharides – complex carbohydrate molecules made my polymerizing simple sugar molecules such as glucose

Proteins – polymers of amino acids formed by condensation reactions.

 

Amino Acids – naturally occurring organic compounds which possess both an –NH2 group and – COOH group on adjacent carbon atoms. There are 20 naturally occurring amino acids, of which glycine is the simplest.

 

Carbohydrates – a group of naturally occurring organic compounds which can be represented by the general formula Cx(H2O)y

Sugars – any of the class of soluble, crystalline, typically sweet-tasting carbohydrates found in living tissues and exemplified by glucose and sucrose. They are tested by warming with Benedicts or Fehlings solutions; if the sugar is present, the colour changes from a blue solution to an orange-red suspension or precipitate.

Starch – made up of 200-300 glucose monomers. Starch turns iodine solution from red-brown to blue-black colour.

Cellulose – made up of about 3000 glucose monomers.