Problem 43 - Chemistry Central Science

Question

Draw the structure of the monomer(s) employed to form each of the following polymers shown in Table \(12.5\) (a) polyvinyl chloride, (b) nylon 6,6, (c) polyethylene terephthalate.

Step-by-Step Solution

Answer

The structures of the monomers for the given polymers are as follows: (a) polyvinyl chloride: \(CH_2=CHCl\) (b) nylon 6,6: adipic acid (\(HOOC-(CH_2)_4-COOH\)) and hexamethylene diamine (\(H_2N-(CH_2)_6-NH_2\)) (c) polyethylene terephthalate: terephthalic acid (\(\begin{array}{c}O\\ ||\\ HO-C-(C_6H_4)-C-H\\ ||\\ O\end{array}\)) and ethylene glycol (\(HO-CH_2-CH_2-OH\))

Step 1: The Monomers of Polyvinyl Chloride

To draw the structure of the monomer used for polyvinyl chloride (PVC), we need to understand that PVC is formed by polymerizing vinyl chloride. Vinyl chloride is an unsaturated hydrocarbon with a molecular formula of C\(_2\)H\(_3\)Cl.

Step 2: The Structure of Vinyl Chloride

Vinyl chloride has a double bond between its two carbon atoms, and one carbon atom is also bonded to a hydrogen atom and a chlorine atom. Using this information, the structure of vinyl chloride can be drawn as shown below: \[CH_2=CHCl\]

Step 3: The Monomers of Nylon 6,6

For nylon 6,6, it is a condensation polymer formed from the reaction between adipic acid (a 6-carbon dicarboxylic acid) and hexamethylene diamine (a 6-carbon diamine). The monomers used in this case are adipic acid and hexamethylene diamine.

Step 4: The Structure of Adipic Acid

Adipic acid is a dicarboxylic acid with 6 carbon atoms, with carboxyl groups at each end of the molecule. Its structure can be drawn as: \[HOOC-(CH_2)_4-COOH\]

Step 5: The Structure of Hexamethylene Diamine

Hexamethylene diamine is an amine with 6 carbon atoms and amine groups at each end of the molecule. Its structure can be drawn as: \[H_2N-(CH_2)_6-NH_2\]

Step 6: The Monomer of Polyethylene Terephthalate

Polyethylene terephthalate (PET) is formed by reacting terephthalic acid (a dicarboxylic acid) and ethylene glycol (a diol). The monomers used in this case are terephthalic acid and ethylene glycol.

Step 7: The Structure of Terephthalic Acid

Terephthalic acid has a benzene ring with two carboxyl groups at opposite ends. Its structure can be drawn as: \[\begin{array}{c}O\\ ||\\ HO-C-(C_6H_4)-C-H\\ ||\\ O\end{array}\]

Step 8: The Structure of Ethylene Glycol

Ethylene glycol has 2 carbon atoms and contains a hydroxyl group at each end of the molecule. Its structure can be drawn as: \[HO-CH_2-CH_2-OH\] In summary, the structures of the monomers for the given polymers are as follows: (a) polyvinyl chloride: \(CH_2=CHCl\) (b) nylon 6,6: adipic acid (\(HOOC-(CH_2)_4-COOH\)) and hexamethylene diamine (\(H_2N-(CH_2)_6-NH_2\)) (c) polyethylene terephthalate: terephthalic acid (\(\begin{array}{c}O\\ ||\\ HO-C-(C_6H_4)-C-H\\ ||\\ O\end{array}\)) and ethylene glycol (\(HO-CH_2-CH_2-OH\))