Doc Brown's GCSE OCR Gateway Science-Chemistry Revision Notes

OCR GCSE Gateway Science Chemistry Module C1 Carbon Chemistry

Unit-Item C1e Designer polymers

1. You should be familiar with the idea that everyday items such as supermarket bags are made from polymers.

2. You should appreciate why technology moves forward with the development of materials focusing on the very wide range of uses that polymers have in the 21st century, including health care.

3. You should also appreciate the issues of disposal of polymers eg methods of disposal and recycling plastics.

4. You should appreciate why technology moves forward with the development of materials precisely matched to need using a variety of contexts to capture different interests (CDs, sports equipment, health contexts etc).

5. Be able to interpret simple information about properties of polymers (plastics) and their uses given appropriate information (but no recall is expected in this context).

6. You may have done some research about waterproof clothing, used a polymer (plastics) identification kit and how local councils dispose of public waste - all good learning experiences.

7. Know that nylon is used in clothing.

8. Know and understand that many polymers are non-biodegradable and so will not decay or decompose by bacterial action.

9. Know some of the ways that waste polymers can be disposed of:

   • a) use of land-fill sites

   • b) burning of waste polymers

   • c) recycling.

10. Suggest the properties a polymer (plastic) should have in order to be used for a particular purpose.

11. Be able to explain why a polymer (plastic) is suitable for a particular use given the properties of the polymer.

12. HT only: Know and understand that the atoms in plastics are held together by strong covalent bonds.

13. HT only: Be able to relate the properties of plastics to simple models of their structure:

    • a) plastics that have weak intermolecular forces between polymer molecules have low melting points and can be stretched easily as the polymer molecules can slide over one another

    • b) plastics that have strong forces between the polymer molecules (covalent bonds or cross- linking bridges) have high melting points, cannot be stretched and are rigid.

14. Be able to compare the properties of nylon and Gore-Tex®:

    • a) Nylon is tough, lightweight, keeps water out and keeps UV light out but does not let water vapour through it which means that sweat condenses.

    • b) Gore-Tex® has all of the properties of nylon but is also breathable.

15. Be able to explain why the discovery of Gore-Tex® type materials has been of great help to active outdoor people to cope with perspiration wetness.

16. HT only: Be able to explain why Gore-Tex® type materials are waterproof and yet breathable

    • nylon laminated with PTFE / polyurethane membrane

    • holes in membrane are too small for water droplets to pass through but are big enough for water vapour molecules to pass through

    • membrane is too fragile on its own and so is combined with nylon.

17. Be able to explain why chemists are developing new types of polymers:

    • a) polymers that dissolve

    • b) biodegradable polymers.

18. Be able to explain environmental and economic issues related to the use and disposal of polymers.

19. Notes:

    • Polymerisation - Addition Polymers - structure, uses and disposal problems

    • SMART MATERIALS - Introduction and notes index PART 6 GORETEX, THINSULATE and TEFLON-PTFE