Question

The most common and least expensive plastic film used for packaging of solid food material is -

• A. Polypropylene
• B. Polyvinylchloride
• C. Polystyrene
• D. Polyethylene

Hint:

Remember the PE types:
- LDPE: Extremely flexible, used for stretch wraps, zip-lock bags, and squeeze bottles.
- HDPE: Stiffer and stronger, used for milk jugs, grocery bags, and plastic caps.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Thermoplastic resins dominate the modern food packaging industry due to their chemical inertness, flexibility, water-barrier properties, and low cost of synthesis.

Step 2: Detailed Explanation:
- Polyethylene (PE) is the most widely produced synthetic polymer in the world.
- It is manufactured by the addition polymerization of ethylene monomers.
- In food packaging, its thin film formats (Low-Density Polyethylene, LDPE, and High-Density Polyethylene, HDPE) are the most common, versatile, and least expensive materials used to package solid foods, snacks, bakery items, and fresh produce.
- It provides an excellent moisture barrier, high flexibility, and heat-sealability, though it has moderate gas (oxygen) permeability.

Step 3: Final Answer:
The least expensive and most common plastic film is Polyethylene, which corresponds to option (D).