Form 01 nylon

Chemical recycling of nylon-6 carpet face fibers has been developed into a closed-loop recycling process for waste nylon carpet.5 The recovered nylon-6 face fibers are sent to a depolymerization reactor and treated with superheated steam in the presence of a catalyst to produce a distillate containing caprolactam. The crude caprolactam is distilled and repolymerized to form nylon-6. The caprolactam... 

In order to establish die feasibility of alkaline hydrolysis with respect to recycling of nylon-4,6, it was necessary to determine whether die recovered oligomers could be repolymerized to form nylon-4,6. For diis purpose, solid-state polymerization was performed on nylon-4,6 oligomers formed via alkaline hydrolysis with 50 wt% NaOH at 165°C for 24 h. The solid-state polymerization process... 

For condensation polymerization, it is necessary to have two functional groups on each monomer and to mix stoichiometric amounts of the reactants. In polyamide production, the starting materials first form nylon salt by proton transfer ... 

Nylons belong to the class of polymers known as engineering polymers that is, they are strong, tough, and heat resistant. We can readily extrude and mold nylons to form a wide variety of useful objects, such as tubing, furniture casters, and automotive air intake ducts. Nylons are commonly spun into filaments or fibers. These can be used directly, or braided, or twisted to form threads, yarns, cords, and ropes, which may be further woven to make fabrics. In their fibrous forms, nylons are used in carpets, backpacks, and hosiery. 

The nomenclature of nylon is based on the number of carbon atoms found in the monomers. Thus, caprolactam, which contains six carbon atoms per molecule is polymerized to form nylon 6. Nylon 46 (pronounced "nylon four six ) is made from 1,4 diaminobutane, which contains four carbon atoms and adipic acid which contains six carbon atoms. The convention that we use to name nylons is summarized in Fig. 23.4. 

The diamine and diacid monomers used to make type AABB nylons are typically rather difficult to handle in their pure form. Diamines are liquids or semisolids at room temperature, while the diacids are crystalline solids. These monomers become much more manageable when they are combined to form nylon salts, as shown in Fig. 23.7 a). Nylon salts are solids that can be easily handled and ensure a stoichiometric balance between the diacid and diamine, which is necessary to produce high molecular weight polymers. In the case of nylon 66, the precursor salt is made by boiling adipic acid and hexamethylene diamine in methanol, from which the nylon salt precipitates. 

For the first method exact equivalence of reactants are used to obtain high Molecular weight polymer. In the first step an aqueous solution of adipic acid is neutralised with hexamethylene diamine to form nylon salt. 

Hydrolytic polymerization of e-caprolactam to form nylon 6 (Sec. 2-8f) is carried out commercially in both batch and continuous processes by heating the monomer in the presence of 5-10% water to temperatures of 250-270°C for periods of 12 h to more than 24 h [Anton and Baird, 2002 Zimmerman, 1988]. Several equilibria are involved in the polymerization [Bertalan et al., 1984 Sekiguchi, 1984]. These are hydrolysis of the lactam to e-amino-caproic acid (Eq. 7-56), step polymerization of the amino acid with itself (Eq. 7-57), and initiation of ring-opening polymerization of lactam by the amino acid. The amino acid is... 

The most common amino acid industrially is caprolactam, which forms Nylon 6, in which the amino group is six carbons away from the carboxylic acid. Your skin can thus be regarded as Nylon 2. Fortunately your skin is not soluble in water, at least in the absence of strong acids or bases. 

Hiramatsu, N. and Hirakawa, S. Melting and transformation behavior of gamma form Nylon 6 under high pressure. Polymer J. 14, 165 (1982)... 

The upper limit of the Newtonian plateau is dependent on Mw and the melt temperature. Commonly, it is roughly in the region y = 10 2s 1. Low viscosity fiber-forming Nylon and polyethylene terephthalate (PET) are important exceptions, as their Newtonian plateau extends to higher shear rates. 

Several oxidative routes are available to change cyclohexane to cyclohexanone, cyclohexanol, and ultimately to adipic acid or caprolactam. If phenol is hydrogenated, cyclohexanone can be obtained directly this will react with hydroxylamine to give cyclohexanone oxime that converts to caprolactam on acid rearrangement. Cyclohexane can also be converted to adipic acid, then adiponitrile, which can be converted to hexamethylenedi-amine. Adipic acid and hexamethylenediamine are used to form nylon 6,6. This route to hexamethylenediamine is competitive with alternative routes through butene. 

The following equations represent the condensation reactions to form nylon, a protein, a polyester and starch respectively, Remember you need only to show how the linkage is formed in each case... 

The two homologous aliphatic diamines are commonly used as bifunctional monomers for polycondensation reactions. Hexamethylenediamine or 1,6-diaminohexane, Cf,H16N2 (CAS No. 124-09-4, PM Ref.No. 1840), which is most well-known as a polyamide (Nylon 66) monomer, is also copolymerized with sebacic acid to form Nylon 6/ 10, or with isophthalic acid. Besides that, it is applied as a curing agent for expoxy... 

The reaction to form nylon can be carried out at the interface of two immiscible liquid layers in a beaker. The bottom layer contains adipoyl chloride,... 

In the polymerization of H2N(CH2)io COOH to form Nylon-11, what weight fraction of the reaction mixture has the structure... 

In the anionic polymerization to form nylon block copolymer, the acyllactam Initiates caprolactam polymerization from the ends of the prepolymer. 

The rubber is segregated as big shapeless patches in a continuous nylon phase (the black domains in the micrograph). When the polymerization conditions are not optimum this can also occur in system 3. "Figure 2D" shows a polymer made according to this system where as a result of premature phase separation the polymer has segregated as big particles (about 3 p) and quite a few active groups have not reacted to form nylon blocks. The interfacial adhesion is very small and the mechanical properties of this polymer are equal to those of a polymer prepared according to system 1. 

Figure 1-26. Flowchart showing steps in the manufacture of nylon 6, 6. facture of nylon 6,6. Specific amounts of the two chemicals are combined in solution to form nylon salt. The salt is purified, polymerised, extruded in ribbon form and chipped into small flakes or pellets. The polymer is then melted and extruded through a spinnerette into cool air, where the filaments are formed. The filaments are then stretched or cold drawn to develop desired properties. Nylon staple is obtained by crimping filament tow and then cutting into short uniform lengths.

Problem 5.14 In a polymerization of H2N(CH2)ioCOOH to form nylon-11, 95% of the functional groups is known to have reacted. Calculate (a) how much monomer (in terms of weight fraction) is left in the reaction mixture, (b) weight fraction of the reaction mixture having a number-average degree of polymerization equal to 100, and (c) the extent of reaction at which the 100-mer has the maximum yield by weight. 

Problem 5.15 In the polymerization of equimolar mixture of H2N(CH2)eNH2 and H02C(CH2)4C02H to form nylon-6,6, 99% of the carboxylic acid groups are... 

In the polycondensation of H2N(CH2)eNH2 and HOOC(CH2)4COOH, in equimolar quantities, to form nylon-6,6 what is the molecular weight of the species that has the largest yield by weight at 99% conversion ... 

The reactants that form nylon are linked together by reactions... 

Which two functional groups react to form nylons Polyesters ... 

S.S9 addition reactions and condensation reactions 15.61 Dispersion forces strongly attract the long, unbranched chains of high-density polyethylene (HOPE). Low-density polyethylene (LDPE) has branching in the chains that prevents packing and weakens the attractions. 15.63 An amine and a carboxylic acid react to form nylon a carboxylic acid and an alcohol form a polyester. 

This is a variation of the reaction to form nylon discussed in the text. 

Figure 9.1 When adipoyl chloride in dichloromethane reacts with hexanediamine, nylon is formed. Nylon is used in many products, including carpeting, clothing, sports equipment, and tires. 

Draw the structures of the monomers used to form nylon 12 and nylon 6,10. 

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