Polymers

Question 1

How can condensation polymers be formed

Answer 1

By the reactions between :

1. Dicarboxylic acids and diols
2. Dicarboxylic acids and diamines
3. Amino acids

Question 2

What are the two types of polymerisation

Answer 2

Addition and Condensation

Question 3

How is an addition polymer formed

Answer 3

When unsaturated monomers react to form a polymer

Question 4

Why are poly(alkenes) chemically inert and non-biodegradable

Answer 4

Due to the strong C-C and C-H bonds and the non-polar nature of the bonds and therefore are non-biodegradable

Question 5

Dicarboxylic acid + diol =

Answer 5

Poly(ester) + water

Question 6

Diacyl dichloride + diol =

Answer 6

Polyester + HCl

Question 7

Dicarboxylic acid + diamine

Answer 7

Poly(amide) + Water

Question 8

Diacyl dichloride + diamine =

Answer 8

Poly(amide) + HCl

Question 9

Why might it be preferred to use an acyl chloride rather than the carboxylic acid to make the ester or amide

Answer 9

The more reactive acyl chloride goes to completion and does not need a catalyst, but if you were to use the carboxylic acid you would need an acid catalyst and would only give and equilibrium mixture so lower yield.

Question 10

Dangers of using acyl chlorides in making esters and amides

Answer 10

Produces hazardous HCl fumes

Question 11

What is the polyester terylene made from

Answer 11

ethane-1,2-diol and benzene-1,4-dicarboxylic acid

Question 12

Uses of the polyester terylene

Answer 12

Clothing and tire cords

Question 13

What is the linkage between the repeating units of terylene

Answer 13

Ester link of -C(O)=O

Question 14

What is the polyamide Nylon 6,6 made from

Answer 14

Hexanedioic acid and Hexane-1,6-diamine

Question 15

What is formed if different length carbon chains are used

Answer 15

Different polyamides are formed

Question 16

Uses of Nylon 6,6

Answer 16

Clothing

Question 17

Uses of Kevlar

Answer 17

Bullet proof vests

Question 18

Why are polyesters not suitable for use under strongly acidic/alkaline conditions

Answer 18

The ester group is hydrolysed by the acid/alkali

Question 19

How are polyesters and polyamides broken down

Answer 19

By hydrolysis

Question 20

Why are polyesters and polyamides not hazardous/harmful to the environment

Answer 20

The ester group can be hydrolysed due to the presence of polar bonds and therefore are attacked by nucleophiles and so polyesters and polyamides are biodegradable

Question 21

Why is it not possible to quote an exact value for the molar mass of a polymer but only an average one

Answer 21

It is made up of molecules of different chain lengths

Question 22

Why do polyesters like terylene not have a sharp melting point

Answer 22

It is made up of molecules of different chain lengths. A mixture does not have a sharp melting point but melts over a range of temperatures

Question 23

What are the forces between polymer chains in polyesters

Answer 23

There are permanent dipole forces between the polar carbonyl groups, C=O, on adjacent carbon chains in addition to the Van der Waals forces between the chains

Question 24

What are the forces between polymer chains in polyamides and proteins

Answer 24

There is hydrogen bonding between the oxygen in the polar carbonyl groups, C=O, and the H in the N-H groups in the different chains. There is also Van der Waals forces.

Question 25

What is the difference in melting points between polyesters and polyamides

Answer 25

Polyamides have higher melting points as there is hydrogen bonding in polyamides which is stronger than the permanent dipole forces in polyesters therefore more energy is needed to overcome the stronger intermolecular forces in polyamides.

Question 26

What are the different types of disposal of polymers

Answer 26

Landfill Sites
Incineration
Recycling

Question 27

Advantages of landfill sites

Answer 27

Most common method

Question 28

Disadvantages of landfill sites

Answer 28

Many are reaching capacity
Most polymers (polyalkenes) are non-biodegradable so take many years to break down
Unsightly

Question 29

Advantages of incineration

Answer 29

Rubbish is burnt and energy produced is used to generate electricity
Volume of rubbish greatly reduced

Question 30

Disadvantages of incineration

Answer 30

Some toxins and greenhouse gases are emitted

Question 31

Advantages of recycling

Answer 31

Saves raw materials such as crude oil

Question 32

Disadvantages of recycling

Answer 32

Polymers need collecting and sorting which is costly
Polymers can only be recycled into the same type so needs careful separation

Question 33

Advantages of using biodegradable polyesters/amides

Answer 33

They do not occupy landfill sites and do not accumulate in the environment

Question 34

What is produced in the base hydrolysis of a polyester, when using hot aqueous NaOH

Answer 34

Sodium salt of the dicarboxylic acid + diol

Question 35

What is produced in the acid hydrolysis of a polyester, using hot dilute HCl

Answer 35

Dicarboxylic acid + diol

Question 36

What is made when two amino acid molecules join together by condensation polymerisation

Answer 36

Dipeptide

Question 37

What is the linkage between two amino acids

Answer 37

Peptide link/amide link -C(=O)-NH-

Question 38

What is produces in the base hydrolysis of polyamides

Answer 38

Sodium salt of the dicarboxylic acid + diamine

Question 39

What is produced in the acid hydrolysis of polyamides

Answer 39

Dicarboxylic acid + ammonium salt of the diamine

Question 40

How do you name aliphatic dicarboxylic acids

Answer 40

-dioic acid

Question 41

How do you name aromatic dicarboxylic acids

Answer 41

-dicarboxylic acid