12.2.2 Environmental Impact of Plastics

Most plastics are highly resistant to degradation due to their strong carbon-carbon backbone. This leads to long persistence to degradation.

What happens:

• As plastics degrade slowly, they can break down into microplastics, which are small particles that can contaminate water bodies.
• These microplastics are harmful to aquatic life and human health.

Incineration:

• While incineration reduces plastic volume, it can release harmful chemicals and greenhouse gases if not properly managed.
• Certain plastics, when burned, can emit toxic substances like dioxins and furans.

Key point: Most plastics are highly resistant to degradation and can break down into harmful microplastics. Incineration can release harmful chemicals and greenhouse gases.

Summary Table

Intermediate Level

Plastics:

• Synthetic materials made from organic polymers.
• Examples: PVC, polyethylene, nylon.
• Can be melted and moulded into different shapes.
• Forms: film, fiber, sheet, tube, bottle, box.

Properties of plastics:

Environmental impact:

• Most plastics are highly resistant to degradation due to their strong carbon-carbon backbone.
• They can break down into microplastics, which contaminate water bodies and are harmful to aquatic life and human health.
• Incineration reduces plastic volume but can release harmful chemicals and greenhouse gases (e.g., dioxins and furans).

Key point: Plastics are synthetic materials made from polymers. Their properties depend on their structure, composition, and processing. They are highly resistant to degradation and can harm the environment.

Solved Example

Example: Explain Why Plastics Are Highly Resistant to Degradation

Question: Explain why most plastics are highly resistant to degradation.

Solution:

Most plastics are highly resistant to degradation due to their strong carbon-carbon backbone. This strong backbone makes them difficult to break down by natural processes, leading to long persistence to degradation.

Final Answer: Most plastics are highly resistant to degradation because of their strong carbon-carbon backbone.

Important Points

• - The word "plastic" is derived from the Greek word "plastikos" which means "malleable" or "moldable" and "plastos" meaning "mouldable".
• - Plastics are synthetic materials made from organic polymers, such as PVC, polyethylene, nylon, etc.
• - These materials can be melted down and then transformed into solid or slightly flexible shapes.
• - They are also referred to as "long carbon chain polymers".
• - The ability of a material to be moulded or malleable during the manufacturing process means that it can be cast, pressed, or extruded into a variety of forms, including film, fiber, sheet, tube, bottle, and box.
• - Properties of plastics:
• 1. Molecular Structure — linear polymers are stronger and more rigid; branched polymers are softer and more flexible; cross-linking gives tough, heat-resistant plastics.
• 2. Chemical Composition — determined by monomer type; additives can enhance properties.
• 3. Temperature and Pressure — affect crystalline structure, transparency, tensile strength, and melting point.
• - Environmental Impact:
• - Most plastics are highly resistant to degradation due to their strong carbon-carbon backbone.
• - They can break down into microplastics, which contaminate water bodies and are harmful to aquatic life and human health.
• - Incineration reduces plastic volume but can release harmful chemicals and greenhouse gases (e.g., dioxins and furans).

Remember

• - Plastic = synthetic material made from organic polymers.
• - Examples: PVC, polyethylene, nylon.
• - Can be melted and moulded.
• - Forms: film, fiber, sheet, tube, bottle, box.
• - Properties depend on molecular structure, chemical composition, and processing conditions.
• - Most plastics are highly resistant to degradation.
• - They can break down into microplastics.
• - Incineration can release harmful chemicals.
• - Microplastics are harmful to aquatic life and human health.

Common Mistakes

Quick Revision

Plastics:

The word "plastic" is derived from the Greek word "plastikos" which means "malleable" or "moldable" and "plastos" meaning "mouldable." Plastics are synthetic materials made from organic polymers, such as PVC (polyvinyl chloride), polyethylene (polyethylene), nylon, etc. These materials can be melted down and then transformed into solid or slightly flexible shapes. They are also referred to as "long carbon chain polymers". The ability of a material to be moulded or malleable during the manufacturing process means that it can be cast, pressed, or extruded into a variety of forms, including film, fiber, sheet, tube, bottle, and box.

12.2.1 Properties of Plastics:

The properties of plastics are directly derived from the characteristics of the polymers they are made from. Some of these are:

1. Molecular Structure: Polymer chains tend to be longer and more durable which can be linear or branched. Branched polymers are softer and more flexible. On the other hand, linear polymers are stronger and more rigid. Cross-linking is also possible, with high cross-linking resulting in tough and heat-resistant plastics, such as vulcanized rubber.

2. Chemical Composition: Chemical composition is determined by the monomer type, which determines the plastic's properties. For example, polyethylene (PE) is flexible and moisture-resistant, while polystyrene (PS) is stiff and brittle. Additives such as plasticizers, stabilizers, and fillers can also enhance the plastic's properties, depending on the processing conditions.

3. Temperature and Pressure: Conditions such as temperature and pressure during polymerisation and moulding affect the plastics' crystalline structure, affecting properties like transparency, tensile strength, and melting point.

12.2.2 Environmental Impact of plastics:

Most plastics are highly resistant to degradation due to their strong carbon-carbon backbone. This leads to long persistence to degradation. As plastics degrade slowly, they can break down into microplastics, which are small particles that can contaminate water bodies. These microplastics are harmful to aquatic life and human health.

Incineration: While incineration reduces plastic volume, it can release harmful chemicals and greenhouse gases if not properly managed. Certain plastics, when burned, can emit toxic substances like dioxins and furans.

60-Second Revision

• Plastic = synthetic material made from organic polymers.
• Examples: PVC, polyethylene, nylon.
• Can be melted and moulded.
• Forms: film, fiber, sheet, tube, bottle, box.
• Properties depend on molecular structure, chemical composition, and processing conditions.
• Most plastics are highly resistant to degradation.
• They can break down into microplastics.
• Incineration can release harmful chemicals.
• Microplastics are harmful to aquatic life and human health.
• Linear polymers: stronger, more rigid.
• Branched polymers: softer, more flexible.
• Cross-linking: tough, heat-resistant.
• ⚠️ Warning: most plastics are highly resistant to degradation — they can persist in the environment for hundreds or thousands of years.