Polymers

Question 1

Condensation polymers

Answer 1

• Reactions between either a dicarboxylic acid and a diol, or dicarboxylic acid + diamine or amino acid + amino acid
• can be polyesters, polyamides or polypeptide (protein)
• each time a link is formed a small molecule (water) is lost, which is why it’s called a condensation reaction

Question 2

Polyesters

Answer 2

• dicarboxylic acid + diol -> polyester + water

- has dip-dip IMF due to the polar C=O bond

Question 3

Polyamides

Answer 3

• dicarboxylic acid+ diamine -> polyamide +water

- can form strong hydrogen bond IMF as has -NH bonds

Question 4

Polypeptide

Answer 4

• as amino acids have both a carboxylic acid and amine functional group they can bond to themselves with peptide links
• have both hydrogen and dip-dip IMF so very strong

Question 5

Hydrolysis

Answer 5

• water molecules can be added back in to split ester, amide or peptide linkages
• acid hydrolysis is reversible. It requires reflux conditions, dilute acid and water. The acid is a catalyst
• base hydrolysis requires reflux conditions with a dilute base and water, and is irreversible
• Polyamides are easier to hydrolyse in acid, polyesters in base hydrolysis

Question 6

Repeating units

Answer 6

• The section of a polymer that repeats ‘n’ number of times
• found by taking a H from the NH2 in diamines, and -OH from the carboxylic acid group. Or by taking H from the -OH in diols and the -OH from the carboxylic acid

Question 7

Disposing of polymers

Answer 7

• Condensation polymers are broken down by hydrolysis because they have polar bonds. This makes them biodegradable
• Burying plastic releases methane gas and contributes to global warming, uses up land and releases toxins
• Burning plastic releases toxins and CO2

Question 8

Recycling polymers

Answer 8

• some types of polymer can be melted or moulded
• some types can be cracked into monomers
• it is easy to contaminate polymers in this process, and collecting and sorting plastics is expensive
• it is impossible to recreate the initial plastic and recycling is technically quite hard
• however it reduces waste, saves on raw materials, and costs less than making from scratch, and less CO2 is produced