Question

Give the structure of the condensation copolymer made from the following monomers: \(\mathrm{HOOCCH}_{2} \mathrm{CH}_{2} \mathrm{COOH}\) and \(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\)

Short answer

The condensation copolymer formed will have the repeating unit \(\mathrm{-OCCH}_{2} \mathrm{CH}_{2} \mathrm{CONHCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}-\).

Step-by-step solution

Identify the functional groups in each monomer

Examine each monomer to identify the reactive functional groups that will participate in the polymerization. In this case, the first monomer, \(\mathrm{HOOCCH}_{2} \mathrm{CH}_{2} \mathrm{COOH}\), contains two carboxylic acid groups (\(\mathrm{COOH}\)). The second monomer, \(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\), has two amine groups (\(\mathrm{NH}_{2}\)).

Determine the type of copolymerization

Since the first monomer has carboxylic acid groups and the second one has amine groups, they will undergo condensation copolymerization to form an amide linkage. This is a typical reaction between a carboxylic acid and an amine.

Draw the repeating unit of the copolymer

During the polymerization process, the carboxylic acid group of the first monomer will react with the amine group of the second monomer, releasing a molecule of water and forming an amide bond \(\mathrm{-CONH-}\). The repeating unit in the copolymer will thus have the structure: \[ \mathrm{-OCCH}_{2} \mathrm{CH}_{2} \mathrm{CONHCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}- \] Make sure to draw the repeating unit with the newly formed amide bonds and indicating the repeating nature of the polymer chain.

Key concepts

Polymer Chemistry

Polymer chemistry is a branch of chemistry that focuses on the creation, characterization, and understanding of polymer molecules. A polymer is a large molecule, or macromolecule, composed of many repeated subunits, known as monomers, linked together. These chains of monomers can exhibit a wide range of properties, which are exploited in plastics, textiles, and many other materials we use daily.

In the case of condensation copolymerization, two different types of monomers react to form a larger molecule while releasing a small molecule, typically water. This process creates polymers with alternating blocks or randomly distributed units from each monomer, leading to materials with unique properties derived from each of the original monomers' chemical structure.

Carboxylic Acid and Amine Reaction

The reaction between a carboxylic acid and an amine is a fundamental chemical process that forms an amide bond. Carboxylic acids \( \mathrm{R-COOH} \) contain a carbonyl group \( \mathrm{C=O} \) and a hydroxyl group \( \mathrm{-OH} \) attached to the same carbon, while amines \( \mathrm{R-NH_{2}} \) consist of a nitrogen atom bonded to hydrogen atoms, alkyl, or aryl groups.

During condensation copolymerization, an amine nitrogen attacks the carbonyl carbon of a carboxylic acid, leading to the formation of an amide linkage \( \mathrm{-CONH-} \) and the elimination of water. This type of reaction is common in producing various polymers, including nylon, which is made from the polymerization of diamines and diacids.

Amide Linkage

An amide linkage \( \mathrm{-CONH-} \) is a kind of chemical bond that connects carboxylic acid and amine monomers in a polymer chain. In polymer chemistry, the formation of an amide linkage is a result of a dehydration synthesis reaction, where water is removed as the carboxylic acid and amine react. This bond is characterized by its strength and resistance to solvents and chemicals, which translates to the physical properties of the polymers it forms.

As illustrated in the step-by-step solution, when drawing the structure of a copolymer, it's essential to correctly depict the amide linkages, as they are crucial to the polymer's structure and function. These linkages provide resistance and stability to the resulting polymer, making them prevalent in high-performance materials.

Functional Groups in Polymerization

Functional groups in polymerization play the critical role of dictating how monomer units will connect and what properties the resultant polymer will possess. In the case of condensation copolymerization, functional groups such as the carboxylic acid (\(-COOH\)) and amine (\(-NH_2\)) are the reactive sites that permit the monomers to link together.

These groups are reactive due to their ability to donate and accept electrons, forming new bonds with corresponding counter-parts. During polymerization, the functional groups not only dictate the type of linkage -- like an amide bond in this example -- but also affect the polymer's melting point, solubility, and mechanical strength. Understanding how these functional groups behave is crucial for chemists to design and synthesize polymers with desired characteristics.