Trade name identification: a copolymer of vinyl chloride and vinylidene chloride is commonly called what?

Introduction / Context:
Trade names historically map to specific polymer chemistries. Correct identification is useful for materials selection and legacy documentation.

Given Data / Assumptions:

• Saran refers to vinylidene chloride-based copolymers (often with vinyl chloride).
• Dacron/terylene are PET polyesters.
• Orlon is an acrylic fibre (polyacrylonitrile-based).

Concept / Approach:
Vinylidene chloride imparts excellent barrier properties to oxygen and moisture. Copolymerising with vinyl chloride improves processability; such materials were marketed as “Saran.”

Step-by-Step Solution:
Map polymer composition to established trade names.Select “Saran” for vinyl/vinylidene chloride copolymers.

Verification / Alternative check:
Packaging films with high barrier performance historically used Saran coatings.

Why Other Options Are Wrong:
Dacron/Terylene: PET polyester; Orlon: acrylic—different chemistries and properties.

Common Pitfalls:
Mixing up legacy trade names with generic polymer families.

Final Answer:
Saran