A - Polymers Flashcards

Question

What are the typical uses of Terylene (PET)?

Answer 1

Used in plastic bottles, clothing, sheets and sails.

Answer 2

Condensation polymers are generally stronger and more rigid than addition polymers. This is because condensation polymers are made up of chains containing polar bonds, e.g C-N and C-O. So there are hydrogen bonds between the polymer chains, as well as permanent dipole-dipole forces and Van der Waals forces which are also present.

Answer 3

This is found by starting at any point in the polymer and stopping when the same pattern of atom begins again.

Answer 4

1. Start with the repeating unit. 2. Break the linkage (at the C-O for a polyester or C-N for a polyamide). 3. Add back the components of water for each ester or amide link.

Answer 5

They are addition polymers made up of non-polar carbon chains. This is what makes them unreactive and chemically inert, and non-biodegradable. Examples: poly(ethene) and polystyrene.

Answer 6

They have polar bonds in their chains, which makes them open to attack from nucleophiles. This means that they can be broken down by hydrolysis and are biodegradable, although this process is very slow.

Answer 7

Because plastics either take a very long time to biodegrade or are non-biodegradable.

Answer 8

1. Burying 2. Burning 3. Reusing 4. Recycling

Answer 9

When the plastic is: 1. Difficult to separate from other waste 2. Not in sufficient quantities to make separation financially worthwhile 3. Too difficult technically to recycle.

Answer 10

Pros: 1. It’s relatively cheap and easy method of waste disposal. Cons: 1. Required areas of land. 2. As waste decomposes, it can release methane (a greenhouse gas). 3. Leaks from landfill sites can contaminate water supplies. 4. We’re producing large amounts of waste so there is a need to reduce landfill as much as possible.

Answer 11

Waste plastics can be burned and the heat can be used to generate electricity. This process must be controlled to reduce the release of toxic gases e.g polymers containing chlorine, such as PVC, produce HCl when burned which is toxic and must be removed. Waste gases from the combustion are passed through scrubbers to do this which can neutralises gases such as HCl by allowing them to react with a base. But waste gases such as CO2 still contribute to the greenhouse effect.

Answer 12

1. Some plastics, such as poly(propane) for example, can be melted and remoulded. 2. Some plastics can be cracked into monomers, and these can be used to make more plastics or other chemicals.

Answer 13

1. Reduces amount of waste going to landfill. 2. Saves raw materials (important as oil is non-renewable). 3. Cost of recycling plastics is lower than making plastics from scratch. 4. Produces less CO2 emissions than burning plastics.

Answer 14

1. It’s technically difficult. 2. Collecting, sorting and processing the plastic is more expensive than burning/landfill. 3. You often can’t remake the plastic you started with, you have to make something else. 4. The plastic can be easily contaminated during the recycling process.