35.3 A2 Level

Degradable polymers

7 flashcards to master this topic

Key Concept Flip

Why are poly(alkenes) like poly(ethene) difficult to biodegrade?

Answer Flip

Poly(alkenes) possess strong, non-polar carbon-carbon bonds and are chemically inert. This inherent stability makes them resistant to breakdown by microorganisms in the environment, hindering biodegradation.

Example: Poly(ethene) in landfill persists for a very long time.
Definition Flip

What type of electromagnetic radiation can degrade some polymers?

Answer Flip

Ultraviolet (UV) radiation can break down certain polymers. The UV photons provide sufficient energy to break chemical bonds in the polymer chain, leading to degradation.

Example: Degradation of polymers in sunlight.
Key Concept Flip

What is the key difference in bonding that makes polyesters and polyamides biodegradable compared to poly(alkenes)?

Answer Flip

Polyesters and polyamides contain polar ester (-COO-) and amide (-CONH-) linkages, respectively, which are susceptible to hydrolysis. Poly(alkenes) contain non-polar C-C bonds which are much more stable and resist hydrolysis.

Definition Flip

Name two conditions that can hydrolyse polyesters and polyamides.

Answer Flip

Acidic and alkaline conditions. The ester and amide bonds in these polymers undergo hydrolysis when exposed to acids or bases, breaking down the polymer chains.

Key Concept Flip

Explain how the structure of a degradable polymer affects its rate of degradation.

Answer Flip

The presence of hydrolysable bonds (like ester or amide links) directly increases degradability. The accessibility of these bonds to water or microorganisms also plays a key role.

Example: More ester links mean faster degradation, and greater surface area also increases degradation speed.
Definition Flip

Define 'biodegradable'.

Answer Flip

A substance that can be broken down into simpler substances (e.g. CO2, water, biomass) by the action of living organisms (bacteria, fungi) or their enzymes. Biodegradable polymers can be broken down naturally.

Key Concept Flip

Describe alkaline hydrolysis of a polyester or polyamide.

Answer Flip

Alkaline hydrolysis involves the reaction of the ester or amide bonds with hydroxide ions (OH⁻) from a base (e.g. NaOH). This process breaks the polymer chain at the ester/amide linkages, forming smaller molecules.

Ready to test yourself?

Practice with MCQ questions to check your understanding of Degradable polymers.

Take Quiz
35.2 Predicting the type of polymerisation 36.1 Organic synthesis