3.12 - Polymerisation Flashcards
Can you describe a condensation reaction?
They form when a water molecule is removes from the species of a reaction.
Can you name the 3 main types of condensation polymers?
- Polyamides
- Polyesters
- Polypeptides
How many monomers are condensation polymers usually formed from?
2
What properties do these monomers forming condensation polymers have?
Each has 2 functional groups
What molecule is eliminated in formation of a polyester?
H20
What are the 2 monomers which form a polyester?
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
What are the 2 monomers used to form a polyamide?
Diamine and dicarboxylic acid
Examples of polyamides?
Nylon, kevlar
If you are making Nylon in the lab, what monomers would you use and why? What molecule would be eliminated?
Use hexane-1,6-diacyl chloride as the rate of reaction is much faster. HCl is eliminated.
What is kevlar use for?
In body armour (bullet proof vests, stab vests), helmets, oven gloves.
Why is kevlar so strong?
Rigid chains and close packing of flat aromatic rings.
What are polypeptides? What is the linkage?
Sam linkage as polyamides. But made from just one amino acid monomer.
Why are poly(alkenes) not degradable?
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
Why does hydrolysis not happen in normal conditions?
Very slow rate in standard conditions
What are the four stages needed when recyling polymers?
Collected -> sorted -> melted -> reformed
Advantages of recycling polymers?
- Saves expense of crude oil and preserves a non-renewable resource
- Reduces landfill
Disadvantages of recycling polymers?
- Energy and manpower is needed for collecting, sorting and melting the polymers, making it expensive
- Can only be done a limited number of times
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.
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.
