9. Biodegradable polymers

Question 1

What are the two categories that bio-polymers can be split into?

Answer 1

• natural bio-polymers
• synthetic bio-polymers

Question 2

What are natural bio-polymers?

Answer 2

• made from natural materials
  
  • cellulose
  • starch
  • polysaccharides

Question 3

What are synthetic polymers?

Answer 3

• made from renewable resources but chemically engineered (synthesised) to break down more quickly

Question 4

What are biodegradable polymers?

Answer 4

• can be made from finite resources such as crude oil
• contain additives that cause it to degrade more quickly than traditional polymers

Question 5

What are the disadvantages of biodegradable polymers?

Answer 5

• produce methane gas when decompose in landfill
• can take high temps to decompose and may leave behind toxic gases
• cannot be recycled

Question 6

What are the disadvantages of bio-polymers?

Answer 6

• natural bio-polymers need land to grow
• cannot be recycled

Question 7

What are biodegradable polymers?
(examples)

Answer 7

• corn starch polymer
• potatopak
• biopol (bio-batch additive) (polyhydroxybutyrate, PHB)
• polylactic acid (PLA)
• polyhydroxyalkanoate (PHA)
• lactide
• glycolide (Lactel and Ecofilm)

Question 8

What are the properties of corn starch polymer?

Answer 8

• natural bio-polymer
• made from high-starch vegetables (corn, potatoes, maize)

Question 9

What are the uses of corn starch polymer?

Answer 9

• packaging products
• straws
• vending cups
• disposable cutlery
• bags
• takeaway food containers

Question 10

What are the properties of potatopak?

Answer 10

• natural bio-polymer
• made from potato starch

Question 11

What are the uses of potatopak?

Answer 11

• single-use food items such as bowls, cutlery, food trays and serviettes
• packaging beads or ‘peanuts’
• bin bags

Question 12

What are the properties of biopol?

Answer 12

• natural bio-polymer
• made from bacteria grown in cultures
• additive to promote degradation
• usually 1% added to thermoplastics

Question 13

What are the uses of biopol?

Answer 13

• packaging products such as film and carrier bags
• vending cups
• nappies
• surgical stitches
• pill coverings

Question 14

What are the properties of PLA?

Answer 14

• synthetic bio-polymer
• made from corn kernels or cane sugar
• fermented to produce lactic acid
• synthesised to produce polylactic acid

Question 15

What are the uses of PLA?

Answer 15

• packaging
• single-use bottles
• carrier bags
• plant pots
• disposable nappies
• medical sutures
• 3D printing

Question 16

What are the properties of PHA?

Answer 16

• natural bio-polymer
• made from bacteria grown in cultures
• fully compostable

Question 17

What are the uses of PHA?

Answer 17

• packaging
• medical uses such as slow release medication patches, films, screws and bone plates

Question 18

What are the properties of lactide?

Answer 18

• synthetic bio-polymer
• fully compostable
• water soluble
• PLA and cellulose based

Question 19

What are the uses of lactide?

Answer 19

• biomedical applications
• slow release medication
• bone repair fixings
• detergent washing sachets

Question 20

What are the properties of glycolide?

Answer 20

• synthetic bio-polymer
• fully compostable
• PLA and cellulose based

Question 21

What are the uses of glycolide?

Answer 21

• food film
• bags
• packaging wrap
• bin bags
• agricultural ground sheet
• flower wrap

Question 22

What does degradation occur in the presence of?

Answer 22

• light (photo-degradable)
• oxygen (oxy-degradable)
• water ((hydro-degradable)

Question 23

What is photo-degradation?

Answer 23

where polymer bonds are weakened and the polymer breaks down with exposure to UV lights

Question 24

What is oxy-degradation?

Answer 24

where the polymer turns into a fine powder with exposure to oxygen
- is subsequently degraded by the action of micro-organisms

Question 25

What is hydro-degradation?

Answer 25

where the polymer quickly breaks down with exposure to water - is subsequently degraded by the action of micro-organisms

Question 26

Why does degradation occur?

Answer 26

- due to the action of micro-organisms - convert material into water, CO2, biomass and possibly methane

Question 27

What is the ability of a polymer to degrade dependent on?

Answer 27

- the structure of the polymer