Question 1: Explain the difference between thermoplastics and thermosetting plastics in terms of their structure and reusability.

Answer: Thermoplastics have a linear or branched structure that allows them to be melted and reshaped multiple times, making them reusable. Thermosetting plastics have a cross-linked structure that, once cured, cannot be melted or reshaped, making them permanent and more heat resistant.

Question 2: Describe two common uses of polyethylene and explain why this material is suitable for these applications.

Answer: Polyethylene is commonly used in plastic bags and bottle caps because it is flexible, lightweight, and resistant to chemicals and moisture, making it ideal for packaging and containers.

Question 3: List three properties of polycarbonate and discuss how these properties influence its applications.

Answer: Polycarbonate is impact-resistant, transparent, and has high heat resistance. These properties make it suitable for use in safety glasses, electronic components, and transparent roofing materials.

Question 4: Design Brief: You need to create a lightweight, durable, and weather-resistant container for outdoor use. Which polymer would you select and why?

Answer: A suitable polymer would be polypropylene because it is lightweight, has good impact resistance, and is resistant to weathering and chemicals, making it ideal for outdoor containers.

Question 5: Draw a simple sketch of a product that could be made from PVC, indicating the main features and why PVC is suitable for this product.

Answer: A sketch of a plumbing pipe or window frame, showing a hollow cylindrical shape or rectangular profile. PVC is suitable due to its durability, chemical resistance, and ease of fabrication.

Question 6: Sketch a cross-section of a typical polystyrene foam insulation panel. Label the key features that provide its insulating properties.

Answer: A cross-section sketch showing a closed-cell foam structure with small, trapped air pockets. Labels should include 'cell walls,' 'trapped air pockets,' and 'rigid outer surface.'

Question 7: Identify two environmental concerns associated with the disposal of polymer-based products and suggest one method to mitigate each concern.

Answer: Environmental concerns include plastic pollution and non-biodegradability. Mitigation methods include recycling polymers to reduce waste and developing biodegradable polymers to lessen environmental impact.

Question 8: Explain how the addition of fillers or plasticisers can modify the properties of polymers. Provide one example for each.

Answer: Fillers, such as calcium carbonate, can increase strength and reduce cost. Plasticisers, like phthalates, make polymers more flexible and soft, as used in flexible PVC tubing.

Question 9: Describe the manufacturing process of injection moulding for polymers and mention one advantage of this method.

Answer: Injection moulding involves heating polymer pellets until molten and injecting the liquid into a mould cavity under pressure. It allows for high-volume production with precise and complex shapes, making it efficient for mass manufacturing.