Which polymer is described as hard, rigid, and tough and used for yoghurt pots?

Which polymer is described as hard, rigid, and tough and used for yoghurt pots?

• A. PMMA
• B. HIPS
• C. Nylon
• D. UPVC

Answer: (B)

Packaging polymers must balance rigidity and toughness to protect contents and withstand handling. High-Impact Polystyrene achieves this by being stiff and rigid like polystyrene, but with a rubbery phase that absorbs impacts, giving real toughness. That combination makes it ideal for yoghurt pots, which need to hold their shape, resist cracking if dropped, and stay cost-effective for mass production. The other options don’t match this balance: acrylic (PMMA) is very hard and clear but can be brittle; nylon is tough but often moisture-absorbent and more expensive for food packaging; unplasticized PVC (UPVC) is very rigid but not typically used for food containers due to regulatory and processing considerations. So the material described is High-Impact Polystyrene.

Packaging polymers must balance rigidity and toughness to protect contents and withstand handling. High-Impact Polystyrene achieves this by being stiff and rigid like polystyrene, but with a rubbery phase that absorbs impacts, giving real toughness. That combination makes it ideal for yoghurt pots, which need to hold their shape, resist cracking if dropped, and stay cost-effective for mass production. The other options don’t match this balance: acrylic (PMMA) is very hard and clear but can be brittle; nylon is tough but often moisture-absorbent and more expensive for food packaging; unplasticized PVC (UPVC) is very rigid but not typically used for food containers due to regulatory and processing considerations. So the material described is High-Impact Polystyrene.