Addition and Condensation Polymers and Polymerization

Key Concepts

• Polymer: large molecules made up of many monomers
• Monomer: simpler substance of which polymer is made
• Addition Polymerization: monomers' double-bonds open up to form continuous chain
• Condensation Polymerization: elimination of smaller molecule when functional groups react

Animated Tutorial

Addition Polymerization

Addition polymers form:

• when unsaturated carbon (organic) molecules react to form a long chain polymer molecule
• and no small molecules or atoms are eliminated during the reaction

The general reaction can be represented as:

where R and R' can represent hydrogen atoms, halogen atoms, alkyl or other carbon-containing side chains.

Monomer Name Monomer Structure	Polymer Name Polymer Structure	Polymer Uses
ethene [ethylene] CH2=CH2	polyethene [polythene or polyethylene, PE] -(-CH2-CH2-)n-	LDPE for sandwich wrap, cling wrap HDPE for water pipes, wire insulation
propene [propylene] CH2=CHCH3	polypropene [polypropylene, PP] -(-CH2-CHCH3-)n-	electrical appliances, automotive applications, ropes, carpets, films
chloroethene [vinyl chloride] CH2=CHCl	poly(vinyl chloride), PVC -(-CH2-CHCl-)n-	indoor electrical conduit, underground water pipes
tetrafluoroethene [tetrafluoroethylene, teflon, PTFE] CF2=CF2	polytetrafluorethene [polytetrafluoroethylene, teflon] -[-CF2-CF2-]n-	Insulation for wires, motors, generators, etc. Anti-stick applications in cookware, bearings.
styrene [vinyl benzene] CH2=CH	polystyrene [poly(vinylbenzene), PS] H | -(C- | H H | C- |     )n-	heat and electrical insulation, pipes
acrylonitrile [vinyl cyanide] CH2=CH-CN	polyacrylonitrile -(-CH2-CHCN-)n-	acrylic fabrics stronger than wool
vinyl acetate CH3COOCH=CH2	polyvinylacetate (PVA) -(-CH3COOCH-CH2-)n-	adhesives, paints

Condensation Polymerization

Condensation polymers form:

• when bifunctional monomers react to form a long chain polymer molecule
• small molecules, such as water, are eliminated during the reaction

Polyesters, polyamides, proteins and polysaccharides such as cellulose, are all examples of condensation polymers.

General reaction between a dicarboxylic acid and a diol:

Example:

terephthalic acid	+	ethylene glycol	→	polyethylene terephthalate (terylene® or dacron®)	+ water
nHOOCCOOH	+	nHO-(CH2)2-OH	→	-(-OCCOO-(CH2)2-O-)n-	+ nH2O

Polyamides form when when the -COOH functional group of one monomer reacts with the -NH₂ functional group of another monomer.
An amide link or peptide bond (-CO-NH-) forms between monomers during the reaction.
H₂O is eliminated in the reaction.

Proteins are naturally occurring polyamides.

General reaction between a dicarboxylic acid and a diamine:

HOOC-R-COOH + H₂N-R'-NH₂     →     HOOC-R-CONH-R'-NH₂ + H₂O

Example:

hexanedioc acid + 1,6-hexanediamine     →     nylon-6,6 + water