what is condensation polymers
form when a water molecule is removed from a species of a reaction
3 types of condensation polymers
Polyamides, Polyesters, polypeptides
what are polyamides
former in a reaction between dicarboxylic acid and a diamine
What are polyesters
Former in a reaction between dicarboxylic acids and a diol, producing an ester linkage
What are polypeptides
Formed from multiple amino acids. Single momomer can produce a polymer due to the presence of both a -NH and -OH grp
How can condensation polymers be broken down
Using hydrolysis. Condensation polymers can be broken down back into the constitutent molecules by the addition of H2O.
This is because water is attracted to the polar regions of the polymer meaning the links can be broken down
it can be attacked by nucleophiles
Use of condensation polymers
Condensation polymers contain polar bonds in the ester and amide links.
Hydrogen bonding and dipoles can also form between seperate polymer chains, holding them together in a strong structure
This makes polymers useful for things such as bulletproof vests and heat protective materials
Why are polyalkenes hard to get rid of as waste products.
Polyalkenes are very inert with non polar bonds meaning they are not easily broken down by species in nature.
They are non biodegradable.
Therefore they have to be broken down by burning which produces harmful products such as SO2 or CO which leads to acid rain
one reason polyester is biodegradable
Can be hydrolysed / can react with acid or base or water / can react with nucleophile
How can polyesters and polyamides be broken down
Through hydrolysis due to the polarity within the polymer molecules.
Therefore they are biodegradable and can be broken down easily in nature by water
Thie means polyster and polyamides can be put into landfill and will gradually break down.
Give the IUPAC name for phthalic acid.
Benzene-1,2-dicarboxylic acid
Give the IUPAC name for lactic acid. CH3
CH(OH)COOH
2-hydroxypropanoic acid
Give the meaning of the term racemic mixture (racemate).
Equal mixture of enantiomers
Explain how you could distinguish between a racemic mixture (racemate) of
lactic acid and one of the enantiomers of lactic acid.
(Plane) polarized light
Suggest an alternative name for the term acidity regulator.
Explain how a mixture of lactic acid and sodium lactate can act as a regulator
when natural processes increase the acidity in some foods.
buffer
Large lactate concentration in buffer
added acid is removed by lactate ion
ratio [HA]
addition polymerisation
monomers join together to form a polymer without the loss of any atoms, unsaturated
which polymer cannot be broken by hydrolysis
polyalkenes
Although Terylene is biodegradeable, it is preferable to recycle objects made from Terylene.
Give one advantage and one disadvantage of recycling objects made from Terylene.
advantage - reduces landfill
disadvantage - cost of collecting
Protein chains are often arranged in the shape of a helix.
Name the type of
interaction that is responsible for holding the protein chain in this shape.
hydrogen bonding
Two plastic objects were manufactured, one from the polyalkene represented by the
repeating unit in part (b)(i) and the other from the polyamide represented by the
repeating unit in part (c).
After use it was suggested that both objects be disposed of as landfill.
Describe an experiment in which you could compare the biodegradability of
these two objects.
heat under reflux with aqueous NaOH
poly(alkene) is inert so no reaction
polyamide is hydrolysed to form acid salt and alcohol
Explain why polyamides are degraded by sodium hydroxide whereas polymers such
as poly(ethene) are not.
Polyamides can be hydrolysed
OH- attacks peptide link and
poly(ethene) non-polar
Which compound can polymerise by reaction with itself?
for a compound to polymerise by itself, it must contain two diff functional grp that can react with reaction to form a polymer chain. this is a condensation reaction
Give two industrial advantages, other than cost, of using ethanoic anhydride rather than ethanoyl chloride in the production of aspirin.
less corrosive
less vulnerable to hydrolysis
less dangerous
less violent
In terms of the intermolecular forces between the polymer chains, explain why polyamides can be made into fibres suitable for use in sewing and weaving,
whereas polyalkenes usually produce fibres that are too weak for this purpose
in polyamides - H bonding
in polyalkenes - van der Waals forces
Stronger forces (of attraction) in polyamides
