The formation of Nylon-6,6 involves a condensation polymerization reaction between two monomers: hexamethylenediamine and adipic acid. The mechanism of polymerization can be broken down into the following steps:1. Monomers: The two monomers involved in the formation of Nylon-6,6 are hexamethylenediamine H2N CH2 6NH2 and adipic acid HOOC CH2 4COOH .2. Nucleophilic attack: The nitrogen atom of the amine group NH2 in hexamethylenediamine acts as a nucleophile and attacks the carbonyl carbon atom of the carboxylic acid group COOH in adipic acid. This forms a tetrahedral intermediate.3. Proton transfer: A proton H+ is transferred from the nitrogen atom in the tetrahedral intermediate to the oxygen atom of the hydroxyl group OH in the carboxylic acid.4. Elimination of water: The tetrahedral intermediate collapses, leading to the elimination of a water molecule H2O and the formation of an amide bond also known as a peptide bond between the nitrogen atom and the carbonyl carbon atom.5. Chain propagation: The reaction continues as more monomers of hexamethylenediamine and adipic acid undergo the same nucleophilic attack, proton transfer, and elimination of water steps, leading to the formation of a long polymer chain. This chain consists of alternating units of hexamethylenediamine and adipic acid, connected by amide bonds.6. Termination: The polymerization reaction continues until the monomers are depleted or the desired molecular weight of the polymer is achieved. The final product is Nylon-6,6, a strong and durable synthetic polymer widely used in the production of fibers, textiles, and various plastic materials.