Chapter 11 : Development Of Plastics For The Future

Question 1

State the main non-renewable material used in the production of plastics {1}

Answer 1

Crude oil (1)

Question 2

State the trend in the global production of plastic each year {1}

Answer 2

Continues to increase (1)

Question 3

State the name of the process required to convert crude oil
into the feedstocks required for plastic manufacture. (2)

Answer 3

Fractional distillation (2)

Question 4

Crude oil is the main source of feedstock for the plastics industry.

(i): Explain how the feedstock is obtained from crude oil. {2}

{ii}: Explain how and why the feedstock is prepared for storage before use. {2}

Answer 4

i): Crude oil undergoes fractional distillation to separate it into different substances including gases that can be used to make plastics.

(ii): The gases obtained by fractional distillation are cooled and liquefied because liquids are much easier than gases to store, transport and use.

Question 5

Identify two pollution problems associated with the use of plastics derived from fossil fuels. {2}

Answer 5

Cannot be broken down by microorganisms. {1}
Incineration produces toxic materials. {1}

Question 6

Name two toxic gases that may be released during
the incineration of plastics (2)

Answer 6

Any two from;
Carbon monoxide / hydrogen cyanide/ hydrochloric acid.

Question 7

List two toxic gases that may be released during the incineration of plastics. {2}

Answer 7

Any two from the following;
Carbon monoxide {1};
hydrogen cyanide {1};
hydrogen chloride {1}.

Question 8

Explain why plastics cause pollution problems in the oceans. {2}

Answer 8

Plastics cannot be broken down by micro-organisms or easily recycled so they build up in the environment creating pollution issues such as the great Pacific garbage patch. (2)

Question 9

If BPE is not recycled, it may be disposed of by incineration. Name two toxic gases that may be released during the incineration of plastics such as BPE. (2)

Answer 9

Any two from:

Hydrogen cyanide [1]
Hydrogen chloride/Hydrochloric acid [1]
Carbon monoxide [1]

Question 10

State 1 application for photodegradable plastic and describe its impact on crops or the environment. {4}

Answer 10

Solarisation {1} Where plastic over film {1} Builds up heat {1} To temperatures harmful to soil pathogens {1}

Question 11

Explain what is meant by the term ‘biodegradable plastic’. {1}

Answer 11

Can be broken down by micro-organisms, bacteria or other biological means. (1)

Question 12

Describe two applications of biodegradable plastics. {4}

Answer 12

• Biodegradable plastics can be used as packaging for single use items such as carrier bags, food packaging and drink and food cartons for the takeaway food industry.

• Films. Biodegradable plastic agricultural films as mulch can be used to supress weeds, increase soil temperature, prevent loss of water and minerals from the soil. It can be ploughed into the soil after use.

Question 13

Identify a piece of laboratory apparatus that could be used to measure the tensile strength of photodegradable plastics. {1}

Answer 13

A Newton meter (1)

Question 14

Explain how oxygen can cause a plastic bag to be broken down at the end of its useful life. {3}

Answer 14

Stage 1 – Additive is included in the basic polymer resin during the manufacturing process. {1}

Stage 2 – Breaks the molecular chains so that at the end of its predetermined service life the plastic starts degrading in the presence of oxygen by a process of oxidation, which is accelerated by light, heat and stress {1}

Stage 3 – Bio-degradation is completed by microorganisms. {1}

Question 15

Explain one other option, apart from the use of an additive, that can be used in modern plastic manufacturing processes to improve biodegradability. {2}

Answer 15

Production of bioplastics {1}
Addition of starch which is digested by microorganisms – breaks up plastics into smaller pieces {1}

Question 16

Describe how a plastic can be modified during the manufacturing process to make it photodegradable. {2}

Answer 16

It is manufactured to contain a chemical additive {1} which absorbs light, attacks the polymer and breaks it down. {1}.

Question 17

Describe one agricultural use of compostable plastics. {2}

Answer 17

Compostable plastics can be used to improve soil composition {1}. They break down in the environment to provide useful soil nutrients {1}.

Question 18

Describe a modern manufacturing process used to address the polluting effect of plastics. {2}

Answer 18

Plastics can be manufactured to include a bond in the structure that breaks down when heated or when it absorbs uv light.This increases their thermal or photodegradability. [2]

Question 19

Describe how bioderived polyethylene (BPE) is produced. {2}

Answer 19

Ethanol from fermentation of crop biomass converted to ethylene {1} Ethylene is then polymerised by addition polymerisation {1}

Question 20

The production of bioderived polyethylene (BPE), is often described as not being ‘a sustainable manufacturing process’. Why is this so? {2}

Answer 20

It is energy intensive process. {1}
And energy used in its production will almost certainly come from a non- renewable source. {1}

Question 21

BPE is an example of a recyclable plastic. What does the letters BPE stand for (1)

Answer 21

Bioderived polyethylene (1)

Question 22

Describe fully how BPE is manufactured, {3}

Answer 22

• A plant such as corn/sugar cane undergoes fermentation to produce ethanol. {1}
• Ethanol is converted to ethylene (dehydration). {1}
• Ethylene then undergoes (addition) polymerisation to form BPE. {1}

Question 23

Explain the term ‘sustainable manufacture of plastics. {2}

Answer 23

Sustainable manufacture of plastics refers to design and development that incorporates replenishable raw materials. {1}
Together with efficient manufacturing and production techniques. {1}

Question 24

Two advantages of moving towards the manufacture of biodegradable plastics are;
• They can be manufactured using renewable materials.
• They reduce environmental pollution.
Describe how each of the points above can be considered as an advantage. {4}

Answer 24

• Renewable raw materials are readily replaced unlike fossil fuels {1} that are used during current production, so the process is more sustainable {
1}.

• There is greater security of supply of feedstocks {1} as there is less reliance on crude oil which can come from politically unstable regions {1}.

Question 25

Assess the need for a global move towards the more sustainable manufacture and use of plastics. Your answer should include three different factors. {6}

Answer 25

* The manufacturing process is energy intensive and releases pollutants into the environment {1}. Alternative manufacturing processes are required which have less of an environmental impact {1}. * The lack of biodegradability {1} means that plastics accumulate in the environment causing damage to marine and land habitats and the organisms they support {1}. * They are made from non-renewable raw materials (crude oil) {1} so alternative, renewable feedstocks will need to be found as crude oil is expected to run out {1}.

Question 26

Discuss how we can move towards the more sustainable manufacture and use of plastic. Include two discussion points on sustainable manufacture and one point on sustainable use.

Answer 26

Sustainable Manufacture 1: Current manufacture uses non-renewable crude oil. Sustainable manufacture means moving to renewable raw materials such as plant materials. {2} 2: Lack of biodegradability leads to build-up of plastic in the environment. Manufacturing processes need to be modified to enhance the degradability of plastics. {2} Sustainable use Global pollution problems – increase in use of single-use plastics globally means an increase in pollution. Sustainable use must include strategies for reducing, reusing and recycling. {2}