Biodegradability and Disposal of Polymers
This page provides a comprehensive overview of the biodegradability of different polymer types and various methods for disposing of plastic waste. It focuses on the chemical properties that influence biodegradability and the pros and cons of different disposal techniques.
The document begins by comparing the biodegradability of addition polymers (polyalkenes) and condensation polymers (polyesters and polyamides). Addition polymers are described as chemically inert and non-biodegradable due to their non-polar bonds between repeating units. This characteristic makes them resistant to nucleophilic attack.
Definition: Nucleophilic attack is a chemical reaction where an electron-rich species nucleophile attacks an electron-deficient species.
In contrast, condensation polymers like polyesters and polyamides are noted to be biodegradable and can be broken down through hydrolysis. This is attributed to the polar bonds between their repeating units, making them susceptible to nucleophilic attack.
Highlight: The key difference in biodegradability between addition and condensation polymers lies in the polarity of their bonds, affecting their susceptibility to chemical breakdown.
The document then delves into three main methods of plastic waste disposal: burying, burning, and recycling. Each method is analyzed for its advantages and disadvantages:
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Burying (Landfill):
- Pros: Cheap and easy method
- Cons: Requires land area, releases methane (a greenhouse gas), and may contaminate water supplies with toxins
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Burning:
- Pros: Heat can be used to generate electricity
- Cons: Produces toxic gases and contributes to the greenhouse effect through CO2 emissions
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Recycling:
- Pros: Reduces waste in landfills, saves raw materials, and produces fewer CO2 emissions than burning
- Cons: Technically difficult, potentially more expensive than other methods, and plastic can be easily contaminated during the process
Example: Recycling involves sorting, processing, and remoulding plastic waste into new objects or breaking it down into other chemicals.
The page concludes by emphasizing the importance of understanding these disposal methods, as plastic waste management is a critical environmental issue. It encourages readers to consider the long-term impacts of each disposal technique on both the environment and the economy.
Vocabulary:
- Biodegradable: Capable of being decomposed by bacteria or other living organisms
- Hydrolysis: A chemical reaction involving the breaking of a bond in a molecule using water
- Polyalkenes: A type of addition polymer formed from alkene monomers
- Polyesters and polyamides: Types of condensation polymers with ester or amide linkages
This comprehensive overview provides valuable insights into the biodegradability of polyesters and polyamides and various methods of plastic waste disposal, which are crucial topics in contemporary environmental science and materials engineering.