Polyamides and Nylon-66, Study notes of Chemistry

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Polyamides Polyamides are polymers with amide linkage (-NH-CO-). Nylon-66 In Nylon-66 both monomers have 6 carbon atoms each and hence the name. Preparation of Nylon-66 Here the polyamide Nylon-66 is formed by heating the reactant mixture under pressure and the process has been developed so that the molecular mass of the polymer is controlled in the range of 12,000 to 20,000 amu. ll It nHO —C—(CH24— C—OH + nH2N—(CH2)s —NH2 ——— Adipic acid Hexamethylene diamine 9 9° Il ll — C= (CH2)4— C —NH(CH2)g — NH | +2nH20 Properties of Nylon-66 High tensile strength, tough, abrasion resistant and elastic. Uses of Nylon-66 It is fabricated into sheets, bristles for brushes and in textiles as crinkled nylon fibers that are used for making elastic hosiery. Nylon-6 or (perlon) Preparation Nylon-6 is prepared from the monomer caprolactum which is obtained from cyclohexane (petrochemical). Since caprolactum is more easily available, it is used for polymerization which is carried out in the presence of water that first hydrolyses the caprolactum to amino acid. Subsequently the amino group of the amino acid can react with caprolactum to form the polyamide polymer. "Filaments of Nylon-6 are obtained by melt-spinning of the polymer. The fibers are cooled by a stream of air. Uses of Nylon-6 i) Nylons are insoluble in common solvents, have good strength and absorb little moisture. ii) It is used for tyre cords, fabrics, ropes, carpets and manufacture of garments.