Low-density polyethylene is flexible, soft, tough and used for plastic bags. Which term is this?

• A. Low-Density Polyethylene
• B. High-Density Polyethylene
• C. Polyvinyl Chloride
• D. Nylon

Answer: (A)

Understanding how a polymer’s structure affects its feel and performance helps explain why this description fits a specific material. Low-density polyethylene has many side branches along the polymer chains, which disrupts tight packing and lowers crystallinity. This makes the material soft, flexible, and tough even when made into thin films—perfect for plastic bags that need to bend and wrap without tearing easily.

In contrast, high-density polyethylene is more linear and packs more tightly, so it’s stiffer and more rigid, suitable for items like containers and piping rather than flexible bags. Polyvinyl chloride can be made rigid or flexible with additives but isn’t the typical soft film material used for bags. Nylon tends to be strong and stiff with different thermal properties, again not the soft bag film described.