Nylon rope trick

As with polyesters, the amidation reaction of acid chlorides may be carried out in solution because of the enhanced reactivity of acid chlorides compared with carboxylic acids. A technique known as interfacial polymerization has been employed for the formation of polyamides and other step-growth polymers, including polyesters, polyurethanes, and polycarbonates. In this method the polymerization is carried out at the interface between two immiscible solutions, one of which contains one of the dissolved reactants, while the second monomer is dissolved in the other. Figure 5.7 shows a polyamide film forming at the interface between an aqueous solution of a diamine layered on a solution of a diacid chloride in an organic solvent. In this form interfacial polymerization is part of the standard repertoire of chemical demonstrations. It is sometimes called the nylon rope trick because of the filament of nylon produced by withdrawing the collapsed film. 

He was also one of the first U.S. scientists to visit postwar Japan. On his first trip in 1956, he was specially honored by a personal audience with Emperor Hirohito. To his hosts delight, he demonstrated with the able assistance of Mimi the "Nylon Rope Trick". In 1957, he returned and was active in the establishment of a polymer section at Professor Sakurada s Institute of Radiation Chemistry near Kyoto. 

How would you improve the strength of the filament produced in the nylon rope trick without... 

Morgan, P.W. 1965. Condensation Polymers by Interface and Solution Methods. Wiley, New York. Morgan, P.W. and Kwolek, S.L. 1959. The nylon rope trick. J. Chem. Ed., 36 182. 

A second classical method for making capsules from emulsions is to form the shell polymer in situ using interfacial polymerization (Morgan and Kwolek 1959 Wittbecker and Morgan 1959). This method is similar to the nylon rope trick often used as a demonstration, where a solution of diacid chloride in organic solvent (such as adipoyl chloride in hexanes) is layered in a beaker with a diamine aqueous phase (such as 1,6-hexadiamine in water Friedli et al. 2005). Because the two monomers meet only at the interface of the two phases, the condensation polymerization to form the polyamide occurs only at the interface. 

Friedli AC, Schlager IR, Wright SW. Demonstrating encapsulation and release a new take on alginate complexation and the nylon rope trick. J Chem Ed 2005 82 1017-1020. 

Scott C, Wu D, Ho CC, Co CC. Liquid-core capsules via interfacial polymerization a free-radical analogy of the nylon rope trick. J Am Chem Soc 2005 127 4160-4161. 

The nylon rope trick . The diamine, 1,6-diaminohexane, is dissolved in water to which some sodium carbonate has been added. A solution of a diacid chloride, adipoyl chloride, in cyclohexane is added and a nylon thread can be pulled from the interface between the two phases. 

If one were to choose more reactive monomers, it would be possible to carry out polycondensations at considerably lower temperatures in solution. For example, consider the reaction of a diamine and a diacid to make a polyamide (nylon), a polymerization that requires relatively high temperatures (see Equation 9). A much faster reaction would occur between the diamine and a corresponding diacid chloride (see Equation 10). Both reactions would produce the same polymer, although the reaction conditions would be much different, and the byproduct HC1 from the acid chloride reaction would have to be carefully trapped. One technique for performing a polymerization such as that in Equation 10 is to dissolve the monomers in different, immiscible solvents, forcing the polymerization to occur only at the interface of the two solvents, a process called interfacial polymerization. Because of the high reactivity of an acid chloride, these reactions can be carried out at very low temperatures. This polymerization can be carried out rather dramatically in a beaker and is known as the nylon rope trick (see Section 4). 

You may have carried out the nylon rope trick in a practical class. The diacid chloride of adipic acid is dissolved in a layer of a heavy organic solvent such as CCI4 and a layer of aqueous hexane-1,6-diamine is carefully placed on top. With a pair of tweezers you can pick up the film of polymer that forms at the interface and draw it out to form a fibre. The reaction is a simple amide formation. 

Condensation reactions can involve the splitting out of molecules other than water. For example, nylon 6,6 can be made from hexamethylene diamine and adipoyl chloride (instead of adipic acid). In this case a molecule of HCI is split or condensed out. There is a neat trick you can perform with this system that is commonly called The Nylon Rope Trick. The acid chloride will dissolve in an organic solvent, such as chloroform, while the diamine will dissolve in water. These two solutions do not want to mix and when carefully added to a beaker they form a phase-separated system. Polymerization can then occur at the interface between the phases (an iriterfacial polymerization), as illustrated in Figure 3-13. 

FIGURE 3-13 Interfacial polymerization— The nylon rope trick.1... 

FIGURE 25.7 The nylon rope trick. Adding a solution of adipoyl chloride (an adipic acid derivative in which the OH groups have been replaced by Cl groups iti cyclohexane to an aqueous solution of hexamethylenediamine causes nylon to form at the interface of the two solutions, which do not mix. It can then be drawn off. 

Morgan, Paul W., and Kwolek, Stephanie L. (1959). The Nylon Rope Trick. oMr-nal of Chemical Education 36 182-184. 

SchoUen-Baumann reaction This involves the use of an add chloride in an esterification or amidation for example, the so-called nylon rope trick reaction is an interfacial condensation between sebacoyl chloride and hexamethylenediamine, producing a polyamide known as nylon-6,10. 

Apparatus A 250-mL beaker, a 5-mL syringe, separatory funnel, apparatus for the Nylon Rope Trick. ... 

A convenient method for preparation of polyesters and polyamides in the laboratory is the reaction of diacid chlorides with diols and diamines respectively (i.e. Schotten-Baumann reactions). These reactions proceed rapidly at low temperatures and often are performed as interfacial polymerizations in which the two reactants are dissolved separately in immiscible solvents which are then brought into contact. The best known example of this is the nylon rope trick where a continuous film of nylon is drawn from the interface as illustrated in Fig. 2.3 for the preparation of nylon 6.10... 

In the beaker method of Morgan and Kvolek (p.l74—5) for the formation of Nylons from a diamine and a diacid-dicbloride, an almost inexhaustible thread or rope can be drawn from the transparent solution. As the rope seems to come out of nothing, it is called The Nylon Rope Trick . 

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