Synthetic Polymers
6 marks · NormalAddition polymers and condensation polymers such as polyesters are used widely in packaging and fabrics. Answer the following questions about these materials.
State what makes addition polymers, such as poly(ethene), difficult to dispose of in the environment.
Landfill and incineration are two ways of disposing of addition polymers. Give one advantage and one disadvantage of using landfill compared to incineration.
Describe briefly how a polyester is made by condensation polymerisation.
Suggest one advantage in terms of disposal if more consumer products were made using polyesters instead of addition polymers.
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(a) Addition polymers do not biodegrade / are inert / are not broken down by bacteria.
(b) Advantage: Landfill does not produce greenhouse/toxic gases. Disadvantage: Landfill uses lots of space / material lasts thousands of years.
(c) A polyester is made when a diol and a dicarboxylic acid react, with water being removed as each ester link forms.
(d) Polyesters may degrade more easily / some are biodegradable, making disposal easier.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · States that addition polymers are non-biodegradable, inert, or not broken down by bacteria.
B2 (b) · 1 mark · Gives a correct advantage of landfill (e.g., no greenhouse/toxic gases released).
B3 (b) · 1 mark · Gives a correct disadvantage of landfill (e.g., uses space, lasts thousands of years, ugly/smelly).
B4 (c) · 1 mark · States that a diol and a dicarboxylic acid react OR the formation of an ester link.
B5 (c) · 1 mark · Mentions the removal of water (condensation).
B6 (d) · 1 mark · Suggests an advantage for polyester disposal (e.g., some are biodegradable/more easily broken down).
Worked solution
a) Addition polymers are difficult to dispose of because they are non-biodegradable; they are not broken down by bacteria naturally.
b) One advantage of landfill over incineration is that landfill does not release greenhouse or toxic gases (such as CO2, CO, or HCl). One disadvantage is that landfill takes up large amounts of land and the plastic remains unchanged for thousands of years.
c) A polyester is made by the reaction between a diol (with two –OH groups) and a dicarboxylic acid (with two –COOH groups). Each time a –COOH group reacts with a –OH group, an ester bond forms and a molecule of water is lost. This is known as condensation polymerisation.
d) One advantage is that some polyesters can degrade more easily or are biodegradable, making their disposal less of a problem compared to addition polymers.