Question

Which among the following is a synthetic polymer? (a) phenol-formaldehyde resin (b) proteins (c) polysaccharides (d) natural rubber

Short answer

(a) phenol-formaldehyde resin is a synthetic polymer.

Step-by-step solution

Identify Synthetic from Natural

Synthetic polymers are human-made, whereas natural ones are derived from nature without significant human intervention. Read through the options to identify which one sounds man-made.

Analyze Each Option

Let's analyze each option: - (a) Phenol-formaldehyde resin is known to be synthetic, created through chemical reactions. - (b) Proteins are natural polymers made from amino acids found in living organisms. - (c) Polysaccharides are natural polymers like starch and cellulose found in plants. - (d) Natural rubber is derived from the latex of rubber trees, hence natural.

Confirm the Synthetic Polymer

Phenol-formaldehyde resin is synthetic, as it's produced industrially through polymerization involving phenol and formaldehyde. The other options are naturally occurring.

Key concepts

Phenol-formaldehyde resin

Phenol-formaldehyde resin is a significant type of synthetic polymer that was one of the first entirely synthetic polymers ever created. It is produced through a controlled chemical process called polymerization. During this process, phenol, a type of alcohol, reacts with formaldehyde, a simple aldehyde, under specific conditions of pressure, temperature, and in the presence of a catalyst. This reaction causes the phenol and formaldehyde molecules to link together, creating a large chain, or three-dimensional network known as a resin.

This synthetic resin is valued for its excellent durability and resistance to heat, chemicals, and electricity. These properties make it a preferred material in manufacturing various products such as electrical insulators, kitchenware, and coatings.

• Durable and heat resistant
• Chemical protective properties
• Used in electronic and household items

Phenol-formaldehyde resin reflects the unique advantages of synthetic polymers in industrial applications, showcasing attributes not typically found in natural polymers.

Natural vs. Synthetic Polymers

Polymers are large molecules composed of repeating structural units known as monomers. The classification into natural and synthetic polymers depends on their origin and manufacturing process. Natural polymers occur in nature and are utilized by living organisms to build structures or store energy. Common examples include proteins, which are fundamental to life processes, polysaccharides such as starch and cellulose which play key roles in biological systems, and natural rubber derived from rubber trees.

On the other hand, synthetic polymers are human-engineered through controlled chemical processes, allowing customization of properties specific to various needs. Examples like nylon, Bakelite, and phenol-formaldehyde resin serve distinct purposes that often extend beyond what natural polymers can provide.

• Natural: Derived from nature, includes proteins and starches.
• Synthetic: Man-made, often through polymerization, includes nylon and phenolic resin.

Understanding the differences between these polymer types helps in selecting appropriate materials for technological and industrial applications.

Polymerization Process

The polymerization process is at the heart of creating both natural and synthetic polymers. Essentially, it's a chemical reaction through which monomers, the smaller basic units, bond together to form polymers, which are larger molecules. There are several types of polymerization processes, but two broad categories are commonly recognized: addition polymerization and condensation polymerization.

In addition polymerization, monomers add to one another without the loss of any small molecules, often resulting in chain-linear polymers. An example includes the polymerization of ethylene into polyethylene, a widely used plastic. Conversely, condensation polymerization involves the joining of monomers while losing small molecules like water or methanol as by-products. Phenol-formaldehyde resin formation is an example of condensation polymerization where water is typically released during the bonding of phenol and formaldehyde.

• Addition polymerization: No by-product, chain growth (e.g., polyethylene)
• Condensation polymerization: By-products released, step-growth (e.g., phenol-formaldehyde resin)

Through these processes, a wide range of materials are created, tailored to meet diverse industrial and consumer needs.