Concept:
Polymers can be broadly classified based on their environmental degradation characteristics into two distinct groups:
• Non-Biodegradable Polymers: Synthetic polymers that are highly resistant to environmental degradation processes by microorganisms due to strong, stable carbon-carbon bonds. They accumulate as waste and contribute significantly to environmental pollution (e.g., Nylon 6,6, Nylon-6, Polyethylene, PVC, Melamine-formaldehyde resin).
• Biodegradable Polymers: Polymers that decompose naturally over time through biological processes mediated by microorganisms (such as bacteria, fungi, or algae). They contain functional groups (like ester or amide linkages) that are susceptible to enzymatic hydrolysis, breaking down into non-toxic environmental updates over time.
Step 1: Analyzing Nylon-2-nylon-6 as a biodegradable copolymer.
Nylon-2-nylon-6 is an alternating polyamide copolymer. It is synthesized by the condensation polymerization of two different amino acid monomers:
• Glycine (\( \text{H}_2\text{N-CH}_2\text{-COOH} \)), which contains 2 carbon atoms.
• Amino caproic acid (\( \text{H}_2\text{N-(CH}_2)_5\text{-COOH} \)), which contains 6 carbon atoms.
Because it contains peptide-like amide bonds with a specific alternating structural arrangement, microorganisms can break down its molecular chain via enzymatic hydrolysis. Therefore, it is a well-known biodegradable polymer.
Step 2: Evaluating the other options for environmental stability.
Let us briefly review the other synthetic options given:
• Nylon 6,6: Formed by the condensation of hexamethylenediamine and adipic acid. Its crystalline structure makes it incredibly tough and non-biodegradable.
• Melamine polymer: A highly cross-linked thermosetting resin formed by the condensation of melamine and formaldehyde, rendering it inert and highly non-biodegradable.
• Nylon-6: Formed by heating caprolactam. Like Nylon 6,6, it is a synthetic polyamide that resists microbial breakdown.
Therefore, only Nylon-2-nylon-6 is a biodegradable option, corresponding to option (B).