Problem 62 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following is biodegradable polymer of polyamide class? (a) dextran (b) Nylon-2-Nylon-6 (c) Nylon-6, 6 (d) PHBV

Step-by-Step Solution

Answer

Nylon-2-Nylon-6 is the biodegradable polyamide polymer.

Step 1: Understanding the Question

The question is asking us to identify which of the given polymers is biodegradable and belongs to the polyamide class. We need to understand what characteristics define a biodegradable polymer and specifically a polyamide.

Step 2: Identify Candidate Polymers

The options given are: (a) dextran - a polysaccharide, not a polyamide. (b) Nylon-2-Nylon-6 - involves amino acids, which are polyamides. (c) Nylon-6, 6 - a synthetic polyamide, but not biodegradable. (d) PHBV (Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)) - a biodegradable polyester, not a polyamide.

Step 3: Analyzing Nylon-2-Nylon-6

Nylon-2-Nylon-6 is a copolymer of glycine (an amino acid) and aminocaproic acid, and it fits the criterion of being a polyamide, as it includes amide linkages.

Step 4: Determining Biodegradability

We must ascertain that the polymer is biodegradable. Natural amino acid-based polymers like Nylon-2-Nylon-6 tend to be more biodegradable due to their natural origin and structure.

Step 5: Final Conclusion

From the analysis, Nylon-2-Nylon-6 is identified as the only biodegradable polymer of the polyamide class among the options.

Key Concepts

Polyamides

Polyamides are a class of polymers characterized by amide linkages (-CONH-) in their main chain. These linkages are formed by the reaction of amino groups (-NH₂) with carboxylic acid groups (-COOH). Polyamides can be both natural, like proteins or synthetic, like nylon.
Common features include:

• High strength and durability
• Resistance to wear and abrasion
• Varied applications from textiles to engineering plastics

An interesting aspect is their ability to vary between synthetic and natural origins. This versatility allows for tailoring their physical properties to specific needs. Knowing the differences between synthetic and natural polyamides is crucial in understanding their applications and biodegradability.

Nylon-2-Nylon-6

Nylon-2-Nylon-6 is a specific type of polyamide that consists of alternating units of glycine and aminocaproic acid. Glycine is the simplest amino acid, and aminocaproic acid is a 6-carbon amino acid. These molecules combine to form amide linkages in the polymer chain.
This structure grants Nylon-2-Nylon-6 several unique characteristics:

• Flexibility: Due to the varied chain lengths of the two monomers
• Biodegradability: As it is derived from amino acids, making it more susceptible to degradation by environmental factors

Nylon-2-Nylon-6's structure represents a bridge between the robustness typical of synthetic polymers and the degradability often seen in natural polymers. It demonstrates how modern chemistry can adapt polymer structures to meet both functional and environmental needs.

Biodegradability Assessment

Assessing the biodegradability of a material involves understanding how it breaks down naturally in the environment. For polymers like Nylon-2-Nylon-6, this depends on several factors:

• The presence of natural monomers: Glycine and aminocaproic acid in Nylon-2-Nylon-6 make it more prone to biodegradation.
• Microbial activity: Natural polymers are more likely to be degraded by microbes due to enzymes that break down the bonds.
• Environmental conditions: Factors such as temperature, moisture, and sunlight also affect the rate of degradation.

Biodegradable polyamides like Nylon-2-Nylon-6 offer a promising solution to reduce plastic waste and its environmental impact. They are specifically designed to break down more easily, aligning with efforts to create sustainable materials. Understanding these assessments can help in developing and choosing environmentally friendly materials for various applications.