CHEMISTRY QUESTIONS AND VERIFIED ANSWERS

CHEMISTRY QUESTIONS AND VERIFIED ANSWERS Condensation Polymers (Edexcel IGCSE Chemistry) - Revision Notes Condensation polymers are polymers formed through a condensation reaction, where two monomers join together with the elimination of a small molecule, typically water or methanol. This is in contrast to addition polymers, where no small molecules are released. ________________________________________ Key Points 1. Definition of Condensation Polymerization • Condensation polymerization is a type of polymerization where each step involves the reaction of two monomers, resulting in the formation of a covalent bond between them and the release of a small molecule, typically water or methanol. 2. Monomers Involved • The monomers in condensation polymerization usually contain two or more functional groups (like -OH, -COOH, or -NH2). Common examples include: o Diols (two hydroxyl groups, -OH) o Dicarboxylic acids (two carboxyl groups, -COOH) o Diamines (two amine groups, -NH2) o Diacyl chlorides (two acyl groups, -COCl) 3. Example of Condensation Polymers • Polyesters: Formed from a reaction between a diol and a dicarboxylic acid. o Example: Terylene (Polyethylene terephthalate, PET)  Monomers: Ethylene glycol (diol) + Terephthalic acid (dicarboxylic acid)  Reaction: HO-CH2CH2-OH+HOOC-C6H4-COOH→(C6H4-COO-CH2CH2-)n+H2Otext{HO-CH}_2text{CH}_2text{-OH} + text{HOOC-C}_6text{H}_4text{-COOH} rightarrow text{(C}_6text{H}_4text{-COO-CH}_2text{CH}_2text{-)}_n + text{H}_2text{O}HO-CH2CH2-OH+HOOC-C6H4-COOH→(C6H4-COO-CH2CH2-)n+H2O • Polyamides: Formed from a reaction between a diamine and a dicarboxylic acid. o Example: Nylon-6,6  Monomers: Hexamethylenediamine (diamine) + Adipic acid (dicarboxylic acid)  Reaction: HOOC-(CH2)4COOH+H2N-(CH2)6NH2→Nylon-6,6+H2Otext{HOOC-(CH}_2)_4text{COOH} + text{H}_2text{N-(CH}_2)_6text{NH}_2 rightarrow text{Nylon-6,6} + text{H}_2text{O}HOOC-(CH2)4COOH+H2N-(CH2)6NH2→Nylon-6,6+H2O 4. Polyester Example: Terylene (PET) • Monomers: o Ethylene glycol (C₂H₆O₂): A diol (contains two -OH groups). o Terephthalic acid (C₈H₆O₄): A dicarboxylic acid (contains two -COOH groups). • Reaction: The -OH group of ethylene glycol reacts with the -COOH group of terephthalic acid, eliminating water and forming ester bonds. This process repeats to form a long chain of repeating units. 5. Polyamide Example: Nylon-6,6 • Monomers: o Hexamethylenediamine (C₆H₁₆N₂): A diamine (contains two -NH₂ groups). o Adipic acid (C₆H₁₀O₄): A dicarboxylic acid (contains two -COOH groups). • Reaction: The -NH₂ group of hexamethylenediamine reacts with the -COOH group of adipic acid, releasing water and forming amide bonds. This process repeats to