This question is about polymers - AQA - GCSE Chemistry - Question 6 - 2018 - Paper 2

The complete structure for poly(propene) can be represented as:

\text{C}_{3\text{H}_6} \rightarrow \text{[C(CH_3)(C)H]}_n

Where 'n' indicates the number of repeating units, with three hydrogens attached to each terminal carbon. The structure should show four single covalent bonds with the addition of a single carbon-to-carbon bond linking the propene units.

Using a mixture of poly(propene) and wool produces a more sustainable carpet because:

1. Poly(propene) is derived from non-renewable resources, while wool is a renewable material.
2. Wool is biodegradable, whereas poly(propene) is not, reducing long-term environmental impact.
3. Carpets made from wool typically require less energy to produce and maintain, making them more environmentally friendly.

When considering materials for firefighter uniforms:

Advantages of Polyester:

• Polyester has better flame resistance compared to poly(propene), making it less likely to ignite.
• Higher melting point minimizes risk of deformation in high temperatures.
• Absorbs less water, ensuring the uniform does not become heavy and is less likely to absorb flammable substances.

Disadvantages of Polyester:

• High density results in less uniform comfort.
• Polyester can retain heat, which could be disadvantageous in hot environments.

Advantages of Poly(propene):

• Lightweight nature provides ease of movement.
• Generally, poly(propene) is cheaper to produce.

Disadvantages of Poly(propene):

• Poor flame resistance, posing a significant risk during firefighting.
• Lower melting point could lead to structural compromise.

In conclusion, while poly(propene) may offer weight advantages, polyester is better suited for firefighter uniforms due to its superior flame resistance and higher melting point, which are critical under emergency conditions.