Question

The repeating units of PTFE are (a) \(\mathrm{F}_{2} \mathrm{C}=\mathrm{CF}_{2}\) (b) \(\mathrm{FCl} \mathrm{C}=\mathrm{CF}_{2}\) (c) \(\mathrm{F}_{3} \mathrm{C}-\mathrm{CF}_{3}\) (d) \(\mathrm{Cl}_{2} \mathrm{CH}-\mathrm{CH}_{3}\)

Short answer

The repeating units of PTFE are \\[ ext{F}_2 ext{C}= ext{CF}_2\\]. Option (a) is correct.

Step-by-step solution

Identify the Polymer

PTFE stands for Polytetrafluoroethylene, which is a synthetic fluoropolymer of tetrafluoroethylene.

Determine the Repeating Unit Formula

In PTFE, the repeating unit is derived from the monomer tetrafluoroethylene, which has the formula \[ ext{F}_2 ext{C}= ext{CF}_2\]. This is the basic repeating structure that polymerizes to form PTFE.

Compare with Given Choices

Examine the given options and identify which one matches with the repeating units of PTFE derived in Step 2. The options are (a) \[ ext{F}_2 ext{C}= ext{CF}_2\], (b) \[ ext{FCl} ext{C}= ext{CF}_2\], (c) \[ ext{F}_3 ext{C}- ext{CF}_3\], and (d) \[ ext{Cl}_2 ext{CH}- ext{CH}_3\].

Select the Correct Answer

The correct answer is (a) \[ ext{F}_2 ext{C}= ext{CF}_2\] as it matches the repeating unit of PTFE.

Key concepts

PTFE

PTFE stands for Polytetrafluoroethylene, a high-performance fluoropolymer known for its impressive properties. Many recognize PTFE by one of its popular brand names, Teflon. This material is widely used in a variety of applications due to its unique characteristics.

Some of its outstanding properties include:

• Excellent non-stick properties, which make it ideal for cookware surfaces.
• Exceptional chemical resistance, allowing it to withstand exposure to harsh chemicals without degrading.
• High thermal resistance, capable of enduring temperatures of up to 260°C (500°F).

PTFE is commonly used in industries ranging from aerospace to electronics, and even in the production of waterproof garments. Its versatility arises from its structure and the strength of the carbon-fluorine bonds that make up the polymer chain.

Polytetrafluoroethylene

Polytetrafluoroethylene, or PTFE, is a kind of polymer that has a long chain molecular structure, where the side chains are fluorine atoms. This polymer is synthesized from the monomer tetrafluoroethylene.

The structure of PTFE is characterized by:

• A linear structure, giving it flexibility and strength.
• A densely packed fluorine shell around the carbon backbone, which contributes to its stability and low surface friction.

Due to its significant qualities, PTFE is a choice material when high performance is necessary. In addition to non-stick applications, PTFE's inert nature makes it suitable for medical devices and laboratory equipment where reactivity with other substances is undesirable.

These properties arise because of its synthesis through the polymerization of tetrafluoroethylene, offering a durable and reliable material with a multitude of uses.

Tetrafluoroethylene

Tetrafluoroethylene is the foundational monomer that forms PTFE. Its chemical formula is \(\text{F}_2\text{C}=\text{CF}_2\), reflecting its composition of carbon and fluorine atoms.

This compound undergoes polymerization to create the long chains that become PTFE.

• The double bond between the carbon atoms is crucial as it allows for the polymerization process, converting individual tetrafluoroethylene molecules into the polymer chains of PTFE.
• The predominance of fluorine atoms provides these polymers with their characteristic resistant properties.

Tetrafluoroethylene must be handled with care due to its flammable and potentially hazardous nature. However, once it forms PTFE, the resulting material is incredibly stable and safe for various uses. Understanding the transformation of tetrafluoroethylene to PTFE provides insight into why PTFE holds such an important place in industrial and consumer applications alike.