Which polymeric material possesses the weakest intermolecular binding forces ?
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Answer: A. Polyisoprene
Explanation
Polyisoprene consists of long hydrocarbon chains held together by relatively weak Van der Waals forces. These nonpolar polymer chains lack strong intermolecular attractions like hydrogen bonding found in other materials. As a result, natural rubber exhibits very weak binding forces between its flexible macromolecular strands. Natural rubber is a polymer of isoprene units possessing a flexible cis-1,4-polyisoprene microstructure. Weak intermolecular forces allow the polymer coils to stretch extensively and recoil when released. Unmodified raw rubber behaves as an elastomer with low resistance to permanent deformation until vulcanized.
Elastic bands and flexible tubing rely on the easy stretching permitted by weak intermolecular forces. Comparing intermolecular forces helps materials scientists understand why different polymers exhibit distinct mechanical profiles. Elastomers require cross-linking to restrict chain slippage despite their weak primary intermolecular attraction. Nylon-66 features strong intermolecular hydrogen bonding between amide groups, resulting in high tensile strength. Polystyrene contains bulky benzene rings that restrict chain movement, creating stronger intermolecular rigidity. Bakelite is a heavily cross-linked thermosetting resin possessing very strong covalent bonds throughout its structure.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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