Question

The blend of polyethylene and polypropylene is:

• A. Immiscible due to enthalpic constraints
• B. Immiscible due to entropic constraints
• C. Miscible as they are polyolefins
• D. Miscible due to comparable solubility parameters

Hint:

Blends of polyolefins like PE and PP are often immiscible due to differences in molecular packing and entropic effects, even though they are chemically similar.

Answer 1

The Correct Option is B

Polyethylene (PE) and polypropylene (PP) are both polyolefins, but they are typically immiscible due to entropic constraints. While both polymers have similar chemical structures, their molecular weights and crystallinity differ significantly, which causes them to be immiscible in most cases. The entropic effects of mixing two dissimilar polymers prevent them from easily forming a stable blend. Thus, the correct answer is (B) Immiscible due to entropic constraints.