Solubility of nylon

Because the solubility of nylons is the key issue, we therefore review the literature based on the solvents in which the SEC work was done. 

Fig. 1. Solubility of nylons 4, 6, 8 and 12 in HCOOH at 25 °C a) concentrations of HCX)OH (wt.-%) at which nylons are directly soluble, b) concentrations of HCOOH (wt-%) at which nylons directly precipitate if water is added ...

Fig. 17. Range of solubility of nylon 4 in the system CaCl2/H20/C2Hs0H ...

Polyamides (nylons) The main types of nylon are oil and petrol resistant, but on the other hand susceptible to high water absorption and to hydrolysis. There are a few solvents such as phenol, cresol and formic acid. Special grades include a water-soluble nylon, amorphous copolymers and low molecular weight grades used in conjunction with epoxide resins. Transparent amorphous polyamides are also now available. 

Which of the following polymers might be water-soluble PE, nylon-6,6, PEO, copolymer containing about 50% ethylene and about 50% acrylic acid units, PVC, and PET. 

The mechanism for the production of nylon-12 from the lactam is similar to that for nylon. However, in the case of nylon-12, the ring opening is more difficult and the rate of polymerization is slower, at least in part owing to the lower solubility of the lactam in water. A catalyst such as an acid, amino acid, or nylon salt can serve as a ring-opening agent. Nylon-12 can also be produced via anionic polymerization, ie, polymerization using an anhydrous alkali catalyst. This process can be quite fast even at low temperatures, eg, a few minutes at 130°C. 

DNP-Amino acids which are soluble in diethyl ether can be separated [19-23] in a number of solvent systems (Table 4.1). The column chromatographic separation of many diethyl ether- and water-soluble DNP-amino acids has been accomplished by Beyer and Schenk [24,25]. They used a column packing material which consisted of nylon powder, and eluted with citrate buffer (pH 3.0) at 30 °C and at a flow-rate of 0.5 ml/min for water-soluble DNP-amino acids. The diethyl ether-soluble amino acid derivatives were eluted with phosphate buffer (pH 8) at 30 °C and at a flow-rate of 0.5 ml/min. The water-soluble compounds were monitored at 313 nm, while 366 nm was used for the diethyl ether-soluble derivatives. The separation of both types of DNP-amino acids with this system is shown in Fig.4.10. 

The adsorption isotherms of acid azo dyes onto water soluble and insoluble polymers containing cyclodextrin were measured in aqueous solution. The adsorption of dyes on both types of polymers increased with increase in the ratio of hydrophobic components in the dyes [38], Dyes derivative of dialkylaminobenzene were used for the dyeing of nylon 6 and 6,6 in the presence of interacting / -CD [39], / -CD showed good levelling properties in the dyeing of polyamide fibers. The observed effect can be due to the formation of complexes between /Acyclodcxtri n and dyes. 

What can you say about the solubility of your nylon sample Does is dissolve in hexane (or cyclohexane) Is it water soluble ... 

Nylon forms only at the interface of the two immiscible solutions because neither of the reagents is soluble in the other solvent. In addition, the nylon polymer is not soluble in either solvent. The rope pulled from the interface is actually a column of nylon filled with solvent and reagents. After washing and drying, the strand is considerably smaller in diameter. It lacks the strength of something like a monofilament fiber because the molecules in our nylon sample have not been oriented by stretching. In addition, the molar mass of our nylon is probably considerably lower than that of a commercial sample. 

As mentioned earlier, soluble salts of cobalt and manganese catalyze oxidation of cyclohexane by oxygen to cyclohexanol and cyclohexanone. Cyclohexanol and cyclohexanone are oxidized by nitric acid to give adipic acid. The oxidation by nitric acid is carried out in the presence of V5+ and Cu2+ ions. These reactions are shown by Eq. 8.8. Adipic acid is used in the manufacture of nylon 6,6. 

PVOH (or tradename PVAL) is a crystalline, white powder soluble in water and alcohols. It is characterized by water solubility, low gas permeability barrier, high resistance to organic solvents other than alcohol, and crystallinity when stretch oriented. Crystallinity allows the material to polarize light. A series of hydrolysis levels of the plastic are available that range from room temperature solubility to those not soluble at all. The major applications of the PVOHs are in elastomeric products, adhesives, films, and finishes. Extruded PVOH hoses and tubing are excellent for use subjected to contact with oils and other chemicals. PVOH is used as a sizing in the manufacture of nylon. 

REMOL GES Liquid is a leveling agent with affinity for dyestuffs. It favorably influences the solubility of dyestuffs, increases their migration power, and regulates the speed of dye absorption. REMOL GES Liquid enables the achievement of considerable tone-on-tone leveling in the dyeing behavior of the various nylon and wool dyestuffs. 

This nylon dye resist concentrate is provided as a water soluble powder. This Nylon resist product will assist in the dyeing of Nylon to level and even dyeing and retard the drying rate. 

Roller pumps are among the least expensive and most widely nsed of all sprayer pumps. They provide moderate volumes (8 to 30 gpm) at low to moderate pressure (10 to 300 psi). Often used on low-pressure sprayers, roller pumps are positive-displacement, self-priming pnmps. The rollers, made of nylon, teflon, or rubber, wear rapidly in wettable powders but are replaceable. A pump that will be subjected to such wear should have a capacity at least 50 percent greater than that needed to supply the nozzles and agitator. This reserve capacity will extend the life of the pump. The pump case is usually cast iron or a nickel alloy. Roller pumps are best for emulsifiable concentrates, soluble powders, and other nonabrasive pesticide formulations (Figure 14B). 

Steuerle and HUle (1959) and Hille (1960) developed a method for the quantitative determination of the N-terminal residues normally present in wool. After treatment with l-fluoro-2,4-dinitrobenzene the wool is hydrolyzed and the ether-soluble DNP derivatives applied to a column of nylon 66 powder and developed with phosphate buffer at 60°C. The DNP derivatives of aspartic acid, glutamic acid, serine, threonine, glycine, alanine, and valine separate cleanly and can be readily determined in the eluates. Hence, it is well suited to the determination of N-terminal residues in normal animal fibers. In its present form, however, it is not suitable for general use with proteins or modified wool fibers as some DNP derivatives, such as those incorporating two DNP groups, are bound so strongly by the nylon that they cannot be eluted. 

The synthesis of cyclohexanone, which is an intermediate in the manufacture of nylon 6 and nylon 6,6 is an important industrial process [1], One of the major current routes for the synthesis of cyclohexanone is the liquid-phase autoxidation of cyclohexane at 125-160 °C and 10 bar followed by the selective decomposition of the intermediate cyclohexyl hydroperoxide, using a soluble cobalt catalyst, to a mixture of cyclohexanol and cyclohexanone [2]. These severe conditions are necessary due to the low reactivity of cyclohexane towards autoxidation. Due to the high reactivity of the products in the autoxidation step conversions must be kept low (<10%) [3,4]. Heterogeneous catalysts potentially offer several advantages over their homogeneous counterparts, for example, ease of recovery and recycling and enhanced stability. Recently we found that chromium substituted aluminophosphate-5 and chromium substituted silicalite-1 (CrS-1) are active, selective and recyclable catalysts for the decomposition of cyclohexyl hydroperoxide to cyclohexanone [5j. 

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