Question

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

Short answer

(a) The structure of a section of Teflon polymer can be represented as: \[ \mathrm{-[CF_{2}-CF_{2}]-[CF_{2}-CF_{2}]-[CF_{2}-CF_{2}]-\cdots} \] (b) The type of polymerization reaction required to form Teflon is **addition polymerization**.

Step-by-step solution

a) Drawing the structure of Teflon

Begin by writing down the monomer formula, which is F2C=CF2. In order to create the polymer structure, we need to break the double bond between the two carbon atoms and connect them with single bonds. This creates a repeating unit that can be extended to represent the polymeric structure: \[ \mathrm{-(CF_{2}-CF_{2})-} \] To represent a section of the Teflon polymer, we can simply extend this repeating unit several times: \[ \mathrm{-[CF_{2}-CF_{2}]-[CF_{2}-CF_{2}]-[CF_{2}-CF_{2}]-\cdots} \] Each carbon atom forms two single bonds with fluorine atoms and one single bond with another carbon atom along the chain.

b) Identifying the type of polymerization reaction

The given monomer contains a carbon-carbon double bond, which is typically involved in addition polymerization reactions. In this case, the double bond between the carbon atoms opens up, forming single bonds with the adjacent carbon, resulting in the formation of a long polymer chain. Thus, the type of polymerization reaction required to form Teflon is **addition polymerization**.

Key concepts

Polymer Chemistry

Polymer chemistry is a branch of science that focuses on studying large, complex molecules known as polymers. These molecules are made up of many repeated subunits, called monomers, which are bonded together to form a long and sometimes intricate chain.

One classic example of a polymer is Teflon, a material whose chemical resistance and non-stick properties have made it popular in cookware and various industrial applications. Teflon is essentially a polymer made by connecting many monomer units of tetrafluoroethylene, which is a compound with the formula \(\mathrm{F}_{2}\mathrm{C}=\mathrm{CF}_{2}\).

In the production of polymers like Teflon, scientists utilize a process known as polymerization, which transforms monomers into a polymer. Understanding the structure and formation of polymers is crucial as they're used extensively in our daily lives, from the plastic bottles we drink from to the rubber tires on our cars.

Addition Polymerization

Addition polymerization is a type of polymerization where monomer units add to each other without the loss of any small molecules, such as water. This process typically involves the opening of a double bond between two carbon atoms to form longer polymer chains.

Teflon's monomers, \(\mathrm{F}_{2}\mathrm{C}=\mathrm{CF}_{2}\), contain double bonds that undergo addition polymerization. During this reaction, the double bonds break, and the carbon atoms form new single bonds with neighboring carbon atoms. This process repeats continuously, adding more monomer units to the growing chain, resulting in a polymer with very high molecular weight.

This type of polymerization is a key reaction in creating many synthetic materials, including plastics, resins, and elastomers. It is favored for its ability to create strong and durable polymers, such as the resistant Teflon.

Polymer Structure

The structure of a polymer plays a significant role in its physical properties and applications. In Teflon, the individual repeating units of \(\mathrm{-(CF_{2}-CF_{2})-}\) join together to form a long chain, where each carbon atom is bonded to two fluorine atoms and the adjacent carbon atom via a single bond.

This specific arrangement of atoms imparts Teflon with its characteristic high chemical resistance and thermal stability. The carbon-fluorine bonds are extremely strong, making the polymer inert and nonreactive, which accounts for its widespread use in situations where a non-stick and corrosion-resistant material is required.

Understanding the polymer structure helps in tailoring materials for specific functions, whether that's to improve their strength, flexibility, or to provide other desirable qualities such as lower density or increased resistance to heat.

Monomer Formula

The monomer formula in polymer chemistry denotes the simple compound that serves as the building block of a polymer. For Teflon, the monomer formula is \(\mathrm{F}_{2}\mathrm{C}=\mathrm{CF}_{2}\), which represents tetrafluoroethylene.

Monomers are usually small, reactive molecules with multiple bonds, like double or triple bonds, which can open up and link with other monomer molecules to form polymers. The way these monomers are designed and the type of bonds they contain are crucial in determining the type of polymerization that can occur and the properties of the finished polymer.

The monomer's structure provides insights into the potential applications of the polymer. For example, the strong carbon-fluorine bonds in the Teflon monomer suggest that the resulting polymer will exhibit great chemical stability, which is exactly what is observed in the Teflon polymer's real-world applications.