polymers

Question 1

definition of a polymer

Answer 1

1. a macromolecule built from very large numbers of monomers, with an average Mr of at least 1000 or 100 repeat units

Question 2

functions of poly(chloroethene)

Answer 2

raincoats, water pipes, electrical insulation, floor coverings

Question 3

functions of poly(tetrafluoroethene)

Answer 3

non-stick coating for cookware

Question 4

functions of poly(propene)

Answer 4

plastic containers, packaging

Question 5

functions of poly(phenylethene)

Answer 5

polystyrene foam

Question 6

functions of poly(vinyl acetate)

Answer 6

surface coatings, adhesives, chewing gum

Question 7

differences between addition VS condensation polymers

Answer 7

1. in addition polymers, repeat units have the same empirical formula as its monomer, while in condensation polymers, repeat units have different empirical formula from its monomer
2. in addition polymers, backbone chain typical contains C-C bonds as monomers typically contain C=C double bonds which undergo addition. in condensation polymers, backbone chain contains ester and/or amide groups

Question 8

why are poly(alkenes) difficult to biodegrade

Answer 8

1. poly(alkenes) are chemically inert because the C-C and C-H bonds are strong and non-polar.
2. hence they do not react with most chemicals include strong alkali or acids

Question 9

why are polyesters and polyamides biodegradable

Answer 9

1. enzymes can hydrolyse the ester and amide linkages over time
2. IMPT: recall hydrogen bonding with alcohol groups and amide linkages

Question 10

why is petroleum a finite resource + functions

Answer 10

1. the world has a limited supply of petroleum, as current estimations tell us that within the next few decades, mankind will have completely depleted this natural resrouce
2. petroleum cannot renew itself at a sufficient rate for sustainable economic extraction
3. petroleum is used to make monomers for most polymers and the energy requirements for their manufacture are far less than their equivalents

Question 11

environmental implications of plastic waste disposal

Answer 11

1. incineration of plastic waste can produce noxious fumes, polluting the air. the CO2 produced can contribute to global warming
2. chemical additives used in plastics may leach into landfills and water sources, causing water pollution
3. larger plastics break down into microplastics which infiltrate water and oil and are consumed by plankton and fish, spreading throughout ecosystems

Question 12

economic implications of plastic waste disposal

Answer 12

1. the use of land as landfill in singapore is not sustainable as there are competing purposes for land in land-scarce singapore
2. incineration of plastic waste consumes energy and incurs cost

Question 13

environmental advantages of recycling plastics

Answer 13

1.

Question 14

environmental advantages of recycling plastics

Answer 14

1. reduce consumption of fresh raw materials, hence conserving our natural resources and non renewable supply of petroleum, as well as our surrounding habitats

Question 15

economic advantages of recycling plastics

Answer 15

1. reduce energy usage and cost to make new products from raw materials and for waste disposal

Question 16

social advantages of recycling plastics

Answer 16

1. new jobs and opportunities in the recycling industry creates a positive social impact

Question 17

environmental challenges of recycling plastics

Answer 17

1. plastics must be sorted from discarded waste and shredded before melting and remoulding into plastic products. if not, the recycled plastic may have inconsistent properties. the recycling process may incur more time and cost, resulting in most costly recycled plastic products
2. more energy may be required to make a produce from plastics compared to aluminium or glass

Question 18

social challenges of recycling plastics

Answer 18

1. public willingness to make lifestyle changes to sort recyclables and separate them from waste