Problem 14 - Chemistry The Molecular Science

Question

Give examples of (a) a synthetic addition polymer, (b) a synthetic condensation polymer, and (c) a natural addition polymer.

Step-by-Step Solution

Answer

(a) Polyethene; (b) Nylon; (c) Natural rubber.

Step 1: Identify Synthetic Addition Polymers

Synthetic addition polymers are typically made from monomers containing a double bond, such as alkenes. A common example of a synthetic addition polymer is polyethene, which is made by the polymerization of ethene monomers.

Step 2: Identify Synthetic Condensation Polymers

Synthetic condensation polymers are formed when monomers combine with the loss of a small molecule, such as water. An example of a synthetic condensation polymer is nylon, which is made through the reaction of diamines with dicarboxylic acids.

Step 3: Identify Natural Addition Polymers

Natural addition polymers occur in nature and often involve the polymerization of unsaturated compounds. Natural rubber is a classic example, consisting of isoprene monomers linked together through an addition process.

Key Concepts

Synthetic Polymers

Synthetic polymers are human-made polymers that have a wide range of applications in our daily lives. Some common examples include plastics, synthetic fibers, and rubbers. These materials are engineered for specific properties, making them invaluable in various industries.

• **Plastics**: Often used in packaging, containers, and toys.
• **Fibers**: These include nylon and polyester, commonly found in clothing.
• **Rubbers**: Used in tires, footwear, and seals.

The creation of synthetic polymers involves chemical reactions that link small units called monomers into long chains and networks. This process allows us to create materials with particular strength, flexibility, or thermal properties that natural polymers sometimes cannot offer.

Natural Polymers

Natural polymers are substances that occur naturally and are essential for life. They are found in every living organism and have various vital functions. Examples include proteins, cellulose, and natural rubber. Unlike synthetic polymers, these polymers are usually biodegradable, which means they can be broken down by natural processes.

• **Proteins**: The building blocks of life, found in muscles, enzymes, and hormones.
• **Cellulose**: A structural component in plants, used in paper and textiles.
• **Natural Rubber**: Harvested from rubber trees, used in tires and latex products.

Natural polymers are typically more environmentally friendly compared to synthetic ones, due to their ability to decompose back into natural substances.

Addition Polymerization

Addition polymerization is a process where monomers with double bonds react to form a polymer chain without the production of by-products. This method is widely used for creating synthetic polymers like polyethylene and polypropylene.

• **No By-products**: The reaction occurs by breaking the double bonds and linking units together, making it efficient in terms of material use.
• **Common Processes**: Includes free radical polymerization and ionic polymerization.

Synthetic polymers like polyethene are produced through addition polymerization. Polyethene, in particular, is used in plastic bags, bottles, and films.

Condensation Polymerization

Condensation polymerization involves a chemical reaction where monomers join together while losing small molecules such as water, ammonia, or alcohol. It's a crucial process for producing many synthetic polymers like nylon and polyesters.

• **By-products**: Unlike addition polymerization, it results in by-product formation, usually small molecules.
• **Key Examples**: Nylon, produced from diamines and dicarboxylic acids, and polyesters, made from alcohols and acids.

Condensation polymers, due to their method of formation, often have different properties compared to addition polymers, including higher resistance to temperature and mechanical stress.