The Development Of Plastics For The Future

Question 1

State the main non- renewable material used in the production of plastic

Answer 1

Crude oil

Question 2

State the trend in the global production of plastic each year

Answer 2

Continues to increase

Question 3

State the name of the process required to convert crude oil into the feedstocks required for plastic manufacture

Answer 3

Fractional distillation

Question 4

Identify two pollution problems associated with the use of plastics derived from fossil fuels

Answer 4

Cannot be broken down by microorganisms

Incineration produces toxic materials

Question 5

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

Answer 5

Carbon monoxide/ hydrogen cyanide/ hydrochloric acid

Question 6

State 1 application for photodegradable plastics and describe its impact on crops or the environment

Answer 6

Option 1
Plastic Mulch
Used as a growth promoter for saplings
In forestry or poor land
Allows soil to be stabilised whilst sapling takes root in otherwise unstable soil

Option 2
Coatings for slow release fertiliser/pesticide pellets
Controlled release of active agent
Particularly where risk of leaching 
Or where risk of run off is high

Option 3 
Germination enhancing in maize
Where the soil temperature is raised 
Above the ambient seasonal temperatures
Thereby speeding up the germination rate

Option 4
Solarisation 
Where plastic over film
Builds up heat
To temperatures harmful to soil pathogens

Question 7

Modern plastic production processes are moving towards the production of biodegradable plastics

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

Answer 7

Can be broken down by micro organisms, bacteria or other biological means

Question 8

Describe two applications of biodegradable plastics

Answer 8

• Biodegradable plastics can be used as packaging for simple 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 suppress weeds, increase soil temperature, prevent loss of water and minerals from the soil. It can be ploughed into the soil after use.
• Improvements of soil structure when the decomposed plastic can make the soil more fertile and improve plant growth.

Question 9

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

Answer 9

A newton meter

Question 10

Incorporating an additive into a polymer during the manufacturing process can enhance the biodegradability of the plastics.

Complete the figure below by identifying the additive which can cause a plastic bag to be broken down at the end of its useful life

Answer 10

Oxygen

Question 11

Explain how the additive in the key above can cause a plastic bag to be broken down at the end of its useful life

Answer 11

Stage 1- Additive is included in the basic polymer resin during the manufacturing process

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

Stage 3- Bio-degradation is completed by microorganisms

Question 12

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

Answer 12

Option 1
Modification of the process to enhance thermal and photodegradation
Addition of different chemical links into long chain molecules of plastic which breaks up when hit by UV light

Option 2
Production of bio plastics
Addition of starch which is digested by microorganisms- break up plastics into smaller pieces

Option 3
Production of compostable plastics
Made from e.g. corn starch fully biodegradable and compostable

Question 13

Many plastics are photodegradable. Describe how a plastic can be modified during the manufacturing process to make it photodegradable

Answer 13

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

Question 14

Describe how bioderived polyethylene (BPE) is produced

Answer 14

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

Question 15

The production of bioderived polyethylene (BPE), is often described as not being ‘a sustainable manufacturing process’.

Why is this so?

Answer 15

It is an energy intensive process

And energy used in its production will almost certainly come from a non-renewable source

Question 16

BPE is an example of a recyclable plastic. What does the letters BPE stand for?

Answer 16

Bioderived polyethylene

Question 17

Describe fully how BPE is manufactured

Answer 17

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

Question 18

The figure below details annual world plastic production. Comment on the trend shown and explain why there is a need for a global move towards more sustainable manufacture and use of plastics

Answer 18

Graph demonstrates the increase global production of plastics

This results in an increased demand for and use of finite natural resources such as oil needed for plastic production

Question 19

Explain the term ‘sustainable manufacture of plastics’

Answer 19

Sustainable manufacture of plastics refers to design and development that incorporates replenishable raw materials

Together with efficient manufacturing and production techniques

Question 20

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

Answer 20

Manufacture using renewable materials;

• Renewable raw materials are readily replaced unlike fossil fuels that are used during current production, so the process is more sustainable
• There is greater security of supply of feedstocks as there is less reliance on crude oil which can come from politically unstable regions
• Finite crude oil supplies are conserved for future generations energy needs and for other uses such as transport

Environmental pollution;

• Biodegradable plastics break down so there is less of a build up of plastics in the environment. This benefits wildlife and reduced the impact on ecosystems.
• The manufacture and disposal of biodegradable plastics produces fewer harmful gases and emissions so there is a lower impact on global warming
• Less plastic in the environment reduced littering and therefore reduces the clean-up costs associated with this