Polymers

Question 1

What is a disadvantage of additional polymers?

Answer 1

They are not biodegradable due to their unreactivity which makes them difficult to dispose.

Question 2

What are the 3 ways to dispose of additional polymers?

Answer 2

1. Burying waste plastic in landfills
2. Recycling plastics (cracking into monomers)
3. Burning waste plastics and the heat used to generate electricity

Question 3

What are the advantages of biodegradable polymers? (3)

Answer 3

1. They are renewable
2. The CO2 emissions in plant based products will be equal to the CO2 uptake during the plants growth.
3. Can save energy compared to oil-based polymers.

Question 4

What are the disadvantages of biodegradable polymers?

Answer 4

1. They still need the right conditions to decompose (moisture and oxygen)
2. More expensive than oil-based

Question 5

What are addition polymers used for?

Why are addition polymers considered useful?

Answer 5

Plastics - they have a low reactivity therefore idea for everyday use such as packaging.

Question 6

How are addition polymers formed?

Answer 6

The double bonds in alkene open up and join together to make long chains - polymers.

Question 7

What is a polymer?

Answer 7

A polymer is a long chain molecule that is made up of many repeating units (monomers)

Question 8

What are addition polymers made from?

Answer 8

Alkenes.

Question 9

What are a 2 strengths of recycling polymers rather than putting them in landfill?

Answer 9

Polymer recycling reduces the amount of waste going to landfill and reduces the use of finite resources such as fossil fuels which are used to crack crude oil

Question 10

What is the process of recycling polymers?

What is a issue that comes up with recycling polymers?

Answer 10

It is a time consuming process - polymers have to be sorted into different categories and afterwards need to be chopped, washed, dried, melted and cast into pellets ready for use.

An issue is that certain polymers such as PVC contains a large amount of toxic chlorine which can be released.

Question 11

What is feedstock recycling?

What is a strength of this method over recycling polymers.

Answer 11

The process where waste polymers are broken down by chemical and thermal processes, into monomers, gases and oils. These products are then used as the raw materials in the production of new polymers and other organic materials.

A strength is that it works with unsorted and unwashed polymers.

Question 12

What are bioplastics?

Answer 12

Polymers made from starch, cellulose, plant oils and plant proteins. They are renewable and sustainable alternative to current polymers which rely on crude oil.

Question 13

What polymers are biodegradable and how are they broken down?

Answer 13

The polyester and polyamide condensation polymers are biodegradable because they can be broken down by hydrolysis reactions.

Question 14

What are biodegradable polymers?

Answer 14

Polymers which can be broken down over time by microorganisms.

Question 15

What are 2 types of biodegradable polymers?

Answer 15

1. Compostable polymers - commonly plant based
2. Photodegradable polymers - contains certain bonds which can be weakened by absorbing light / UV. A lot of photodegradable polymers are oil based.

Question 16

What is a condensation polymer?

Answer 16

A polymer is produced by repeated condensation reactions between monomers. Condensation reactions eliminate a water molecule, condensation polymers do this and can also eliminate a small molecule.

Question 17

What are 3 ways that condensation polymers can be formed?

Answer 17

dicarboxylic acids and diols

dicarboxylic acids and diamines

amino acids.

Question 18

How are condensation polymers identified?

Answer 18

The monomers are linked by ester or amide bonds.

Question 19

How is a polyester formed?

Answer 19

A condensation reaction between a dicarboxylic acid monomer and a diol monomer. Water is eliminated and an ester bond / link is formed.

Question 20

What is a hydrocarboxylic acid and how can it be used to form a polyester?

Answer 20

A hydrocarboxylic acid is a single monomer containing both of the key functional groups of an alcohol and a carboxylic acid. Water an be eliminated and forms an ester link.

Question 21

How are polyamides formed?

(2 ways)

Answer 21

A diamine and a dicarboxylic acid are required and form repeating units which are bonded together by amide links, the formula for an amide group is -CONH.

A dioyl dichloride can also be used to react with the diamine instead of the acid. This is a more reactive monomer but more expensive than dicarboxylic acid.

Water is eliminated in both ways, the OH from the dicarboxylic acid and one H from the diamine is removed (H2O).

Question 22

What is used to form a dipeptide?

Answer 22

2 amino acids. The amine group (NH2) and the acid group (-COOH) of each amino acid is used to polymerise with another amino acid.

Question 23

How are polyamide broken down?

(2 ways)

Answer 23

By hydrolysis. Adding water to break the bond.

There are 2 methods of hydrolysis.
1. In acidic hydrolysis, the acid e.g. HCl acts as a catalyst. Polyamides are heated with the dilute acid, this reaction breaks the polyamide into a dicarboxylic acid and ammonium ions.

2. In alkaline hydrolysis, the polyamide is heated with a species containing hydroxide ions e.g. NaOH. This breaks the polymer into sodium salts and its monomers (dicarboxylic acid salt and diamines)

Question 24

How are polyesters broken down?

Answer 24

Hydrolysis - adding water to break the bond.

Acidic and alkaline hydrolysis is used to break the ester link.

Acid hydrolysis forms the diol and dicarboxylic acid

Alkaline hydrolysis forms the diol and dicarboxylic acid salt.