Problem 117 - Chemistry: The Central Science in SI Units, Global Edition

Question

Teflon is a polymer formed by the polymerization of \(\mathrm{F}_{2} \mathrm{C}=\mathrm{CF}_{2} .(\mathbf{a})\) Draw the structure of a section of this polymer. (b) What type of polymerization reaction is required to form Teflon?

Step-by-Step Solution

Answer

(a) A section of the Teflon polymer, with three monomer units connected together in a chain, has the structure: \( -(F_2C-CF_2)_3- \). (b) Teflon is formed through addition polymerization or chain-growth polymerization.

Step 1: Draw the repeating unit of Teflon

To draw the structure of a section of Teflon, we first need to recognize that Teflon is a polymer, which consists of repeating units called monomers. The monomer of Teflon is F2C=CF2. A section of the polymer will have a chain of these monomers connected to each other. To draw the polymer structure, we replace the double bond between the carbon atoms with a single bond and connect the two carbon atoms to the two fluorine atoms.

Step 2: Draw a section of the Teflon polymer

We will now draw a section of the polymer, showing three monomer units connected together in a chain. Each carbon atom forms a single bond with its adjacent carbon atom and remains bound to the two fluorine atoms as well. The structure of a section of Teflon with three monomer units is: \( -(F_2C-CF_2)_3- \)

Step 3: Identify the type of polymerization reaction

The type of polymerization reaction required to form Teflon can be determined by analyzing the monomer structure. The monomer, F2C=CF2, contains a double bond between two carbon atoms. This suggests that the polymerization reaction involves breaking the double bond and forming single bonds with other monomers. Such a reaction is called an addition polymerization or chain-growth polymerization. To summarize, (a) The structure of a section of Teflon is \( -(F_2C-CF_2)_3- \). (b) The type of polymerization reaction required to form Teflon is addition polymerization or chain-growth polymerization.

Key Concepts

Teflon

Teflon is a widely recognized polymer known for its non-stick properties, often used in cookware. But what makes Teflon unique at the molecular level? It is primarily composed of carbon and fluorine atoms, forming a series of repeating units. This polymer is created from the monomer

• Structurally, Teflon consists of a single carbon backbone with two fluorine atoms attached to each carbon.
• The arrangement provides Teflon with its distinctive slippery surface, which is resistant to sticking and highly stable.

These chemical properties make it not only useful in the kitchen but also valuable in a variety of industrial applications, offering resistance to both heat and chemical reactions.

Addition Polymerization

The process of forming Teflon revolves around a chemical reaction called addition polymerization. This type of reaction is crucial because it allows small monomer molecules to link together and form a larger polymer chain. In the case of Teflon:

• The carbon-carbon double bonds in the monomer \( \text{F}_2\text{C} = \text{CF}_2 \) are broken during the reaction.
• Once broken, these monomers can form new connections known as single bonds with neighboring monomer units.
• This reaction continues, adding one monomer unit at a time to the growing polymer chain.

Overall, addition polymerization is also known as chain-growth polymerization, as it builds the polymer step by step, extending the chain rapidly.

Monomer Structure

Understanding the monomer structure is key to grasping how polymers like Teflon are synthesized. A monomer is essentially the smallest part of a polymer that repeats. For Teflon, the monomer is tetrafluoroethylene, \( \text{F}_2\text{C} = \text{CF}_2 \).

• This structure includes:
  • a pair of carbon atoms joined by a double bond, and
  • each carbon atom is bonded to two fluorine atoms.
• The carbon-fluorine bonds are incredibly strong, contributing to Teflon's robustness.
• The presence of the double bond is critical, as it is what enables the monomers to chemically join through addition polymerization, forming the final stable polymer structure.

By knowing these details about each monomer, we can predict and understand the behavior and properties of the resulting polymer.