Which material is described as tough and flexible?

• A. HDPE.
• B. PVC.
• C. MF.
• D. LDPE.

Answer: (D)

This item tests how the molecular structure of polymers affects toughness and flexibility. Low-density polyethylene has a highly branched chain structure, which lowers crystallinity and reduces intermolecular forces. This lets the polymer chains move more easily under stress, giving LDPE a good combination of toughness and flexibility, even at low temperatures. That flexibility plus the ability to absorb energy makes it a go-to material for flexible films and bags.

In contrast, high-density polyethylene is more linear and crystalline, so it’s tougher and stiffer but less bendable. PVC is usually rigid unless softened with plasticizers. MF (a rigid thermosetting resin) is hard and brittle, not flexible. So the material described as tough and flexible is LDPE.