6.2.3 polyesters and polyamides

What is condensation in terms of polymers?

Small molecule eliminated (usually H2O) to form a larger molecule

How many monomers are condensation polymers usually formed from?

two

What properties do these monomers forming condensation polymers have?

Each has two functional groups

Examples of condensation polymers?

Polyesters Polyamides Polypeptides

What molecule is eliminated in formation of a polyester?

H 2O

What are the two monomers which form a polyester (generic names and structures)?

)? Diol and dicarboxylic acid or a molecule with both alcohol and a carboxylic acid functional groups

What is Terylene used for?

As a fibre for making clothes

Which molecule is eliminated when a polyamide is formed?

H 2O

What are the two monomers used to form a polyamide (generic names and structures)?

)? Diamine and dicarboxylic acid

Examples of polyamides?

Nylon, Kevlar

Draw the repeating unit of Nylon-6,6.

6 6

If you are making Nylon in the lab, what monomers would you use and why? What molecule is eliminated?

Use hexane-1,6-diacyl chloride as the rate of reaction is much faster. HCl is eliminated

What is Kevlar used for?

In body armour (bullet proof vests, stab vests), helmets (e.g. F1 drivers’), oven gloves

Why are poly(alkenes) not biodegradable?

Non-polar C-H and C-C bonds

Why is it bad to burn poly(alkenes)?

)? Releases CO2, CO, C (soot) and other toxic chemicals from monomers

Where do most poly(alkenes) end up?

Landfill sites

Why can condensation polymers be broken down?

They have polar bonds

How are condensation polymers broken down?

Hydrolysis (opposite of condensation)

What is the difference between addition and condensation polymerisation?

Condensation makes the polymer and eliminates a small molecule; addition polymerisation breaks C=C to form only one product (just the polymer)

Explain hydrogen bonding between polyamides.

Both C=O and N-H are polar bonds, as N’s electronegativity > H’s and O’s electronegativity > C’s. Hydrogen bonding between H + and O - in different molecules Uses the lone pair of electrons on the O atom

Why do polyesters not show hydrogen bonding?

All O-H bonds are removed during polymerisation