Question:
Crystallization is favored in polymer melts when the chain entanglement is ............ and only polymers with .................. molecular arrangement can crystallize.
Crystallization is favored in polymer melts when the chain entanglement is ............ and only polymers with .................. molecular arrangement can crystallize.
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Crystallization in polymers is possible only for polymers with high stereoregularity, regular chain structures, and minimum chain entanglement.
Updated On: Aug 27, 2025
- maximum, ordered
- minimum, random
- maximum, random
- minimum, ordered
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The Correct Option is D
Solution and Explanation
Step 1: Condition of chain entanglement.
- For crystallization, polymer chains must align in a regular pattern. - If entanglement is high (maximum), chains cannot arrange into ordered structures. - Hence, crystallization requires minimum entanglement.
Step 2: Molecular arrangement.
- Only polymers with an ordered molecular arrangement (regular and repeating structure) can crystallize. - Polymers with random arrangement are amorphous and cannot form crystalline regions.
Step 3: Evaluate options.
- (A) Maximum, ordered → incorrect (high entanglement prevents crystallization).
- (B) Minimum, random → incorrect (random structure cannot crystallize).
- (C) Maximum, random → both wrong.
- (D) Minimum, ordered → correct. Final Answer: \[ \boxed{\text{(D) minimum, ordered}} \]
- For crystallization, polymer chains must align in a regular pattern. - If entanglement is high (maximum), chains cannot arrange into ordered structures. - Hence, crystallization requires minimum entanglement.
Step 2: Molecular arrangement.
- Only polymers with an ordered molecular arrangement (regular and repeating structure) can crystallize. - Polymers with random arrangement are amorphous and cannot form crystalline regions.
Step 3: Evaluate options.
- (A) Maximum, ordered → incorrect (high entanglement prevents crystallization).
- (B) Minimum, random → incorrect (random structure cannot crystallize).
- (C) Maximum, random → both wrong.
- (D) Minimum, ordered → correct. Final Answer: \[ \boxed{\text{(D) minimum, ordered}} \]
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