13. Condensation polymers

What is condensation polymerization?

• A reaction where monomers with reactive functional groups at both ends join to form a polymer, releasing a small molecule (e.g., H₂O or HCl).

What is esterification?

A condensation reaction between an alcohol (-OH) and a carboxylic acid (-COOH), forming an ester linkage and releasing water.

What is condensation polymerization?

• A reaction where monomers with reactive functional groups at both ends join to form a polymer, releasing a small molecule (e.g., H₂O or HCl).

What is esterification?

A condensation reaction between an alcohol (-OH) and a carboxylic acid (-COOH), forming an ester linkage and releasing water.

Why are esters important?

They have pleasant odors and are found in fruits, flowers, perfumes, and flavoring agents.

How does condensation polymerization differ from esterification?

Polymerization involves monomers with two functional groups at both ends, allowing continuous chain formation.

What is a polyester?

A polymer formed by ester linkages in a condensation reaction.

How does condensation between two different monomers occur?

One monomer has the same functional group at both ends, while the other has a different functional group, forming an alternating polymer structure.

What is nylon-6,6 made from?

A condensation reaction between hexanedioic acid and hexane-1,6-diamine, forming amide linkages.

What type of polymer is nylon-6,6?

A polyamide, due to the presence of multiple amide (–CONH–) linkages.

How can a single monomer undergo condensation polymerization?

If it contains two different functional groups (e.g., hydroxyl and carboxyl), it can react with itself to form a polymer.

What is an example of a self-condensing monomer?

• 3-hydroxypentanoic acid, which contains both hydroxyl (-OH) and carboxyl (-COOH) groups.

What are proteins made of?

Proteins are polypeptides, polymers made of 2-amino acids linked by amide (peptide) bonds.

What functional groups allow amino acids to form polymers?

Amino (-NH₂) and carboxyl (-COOH) groups, which link via condensation polymerization.

What is an amide bond in proteins also called?

A peptide bond.

Why do addition polymers have 100% atom economy?

• All reactant atoms are used in the polymer, with no byproducts.

How does condensation polymerization differ from addition polymerization?

• Addition polymerization requires C=C bonds, while condensation polymerization uses functional groups.

• Condensation polymerization releases a small molecule (H₂O or HCl), while addition polymerization does not.

• Condensation polymers can be hydrolyzed, while addition polymers are generally inert.

What small molecule is released when a hydroxyl (-OH) and carboxyl (-COOH) group react?

Water (H₂O), forming a polyester.

What small molecule is released when a carboxyl (-COOH) and amino (-NH₂) group react?

Water (H₂O), forming a polyamide.

What small molecule is released when two hydroxyl (-OH) groups react?

Water (H₂O), forming a polyether.

What small molecule is released when an acyl chloride (-COCl) and an amino (-NH₂) group react?

Hydrogen chloride (HCl), forming a polyamide.

What is hydrolysis in polymer chemistry?

The reverse of condensation polymerization, breaking polymers back into monomers using water.

What is Kevlar, and how is it formed?

A strong polyamide polymer formed via condensation polymerization, used in bulletproof vests.

What functional group forms amide linkages in Kevlar?

The –CONH– group.

What feature of Kevlar allows hydrogen bonding between chains?

Hydrogen atoms bonded to nitrogen (N–H) and lone pairs on oxygen (C=O).

What is the byproduct of Kevlar polymerization?

Water (H₂O).

What happens when Kevlar chains are aligned?

Hydrogen bonding occurs, making it extremely strong.

How does the structure of Kevlar contribute to its strength?

• Linear structure allows strong hydrogen bonding.

• Rigid polymer chains create high tensile strength.

Thermal Stability of Condensation Polymers

Strong intermolecular forces increase melting points.

Uses of Condensation Polymers

• Polyesters → Clothing, packaging, plastic bottles.

• Polyamides (Nylon, Kevlar) → Ropes, bulletproof vests, airbags.