Unit 3: Section 7 - Polymers Flashcards
What is condensation?
Small molecule eliminated (usually H2O) to form a larger molecule
How many monomers are condensation polymers usually formed from?
2
What properties do the monomers forming condensation polymers have?
Each has 2 functional groups
What are 3 examples of condensation polymers?
- Polyesters
- Polyamides
- Polypeptides
What are the 2 monomers which form a polyester?
- Diol and carboxylic acid or a molecule with both alcohol and a carboxylic acid functional groups
What monomers is Terylene made from?
Benzene-1,4-dicarboxylic acid and ethane-1,2-diol
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
What are 2 examples of polyamides?
Nylon and Kevlar
Which monomers is Nylon-6,6 made from?
1,6-diaminohexane and hexane-1,6-dioic acid
H2N-(CH2)4-NH2 and HOOC-(CH2)4-COOH
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 must faster
HCl is elimated
What is Kevlar used for?
In body armour (bullet proof vests, stab vests), helmets (F1 drivers), oven gloves
Which monomers is Kevlar made from?
1,4-diaminobenzene and benzene-1,4-dicarboxylic acid
Why is Kevlar so strong?
Rigid chains and close packing of flat aromatic rings
Why are poly(alkanes) not biodegradable?
Non-polar C-H and C-C bonds
Why is it bad to burn poly(alkanes)?
Released CO2, CO, C (soot) and other toxic chemicals from monomers
Where do most poly(alkenes) end up?
Landfill sites
Why can condesation 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 4 stages needed when recycling polymers?
- Collected
- Sorted
- Melted
- Reformed
What are the advantages of recycling polymers?
- Saves expense of crude oil and preserves a non-renewable resource
- Reduces landfill
What are the 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 does draw the polymer mean?
Draw with square brackets, n, and trailing bonds
What does draw the repeating unit mean?
Just draw the molecule, with trailing bonds
No brackets or n
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 1 product
How do hydrogen bonds arise between polyamides?
- Both C=O and N-H are polar bonds - N’s electronegativity > H’s and O’s > C’s
- Hydrogen bonding between Hδ+ and Oδ- in different molecules
- The lone pair on the O is attracted to the Hδ+
Why do polyesters not show hydrogen bonding?
All O-H bonds are removed during polymerisation
