SEQUENCE B The Stepwise Synthesis of Nylon

Purpose. The important industrial polymer, n)4on-6,6, is prepared by the technique of step-growth polymerization. The physical properties of the polymer are examined. The two monomers used in the polymerization are synthesized. 

Background of an Industrial Polymer. The type of polymerization used in the nylon preparation described in this series of experiments is called step-growth polymerization. The technique uses two different difunctional monomers that undergo ordinary organic reactions. In the present case an add chloride is treated with an amine to produce an amide linkage. 

Nylon is a polyamide. In industry it is produced by reaction of two difunctional monomers (or comonomers) a dicarboxyUc add and a diamine. The polymer that you are going to study is of great historical significance in polymer chemistry, because it was the first of the pol) amides to be recognized as possessing excellent physical properties for forming very strong fibers. Nylon-6,6 was, in fact, the first commerdally produced synthetic polyamide.The 6,6 nomenclature refers to the number of carbon atoms in each of the two comonomers. Industrially, nylon-6,6 is prepared from 1,6-hexanediamine (hexamethylenediamine) and hexanedioic acid (adipic add)  

Numerous combinations of diacids and diamines have been evaluated as fiber materials. However, only a few have reached commercial production, which depends on low-cost, easy-to-access intermediates, and satisfactory general and physical properties of the polymer. One such group of materials are the Aramid class of fibers, which are prepared from aromatic monomers (see Experiment [B3], Question 7-47). One trade name for a material prepared from these type of fibers is Nomex. It has a high degree of heat and flame resistance. Race car driving suits are made from it, and it is also used as an insulator in the space shuttles. 

Nylon-6,6 was first synthesized in 1899 by Gabriel and Maas in Germany. It was not until 1929, however, that the substance was shown to possess practical commercial properties. It was Carother s research program on polyamides 

---