Nylon chains

Effect of Fiber Properties. Acid dyes are attracted to the accessible amine ends of the nylon chains located in the amorphous regions of the fiber. Acid dye affinity of nylon can be adjusted by a dding excess diamine or diacid to the polymer salt or by changing the molecular weight in polymerization. A light acid-dyeable nylon-6,6 is spun with 15—20 amine ends, expressed in terms of gram equivalents per 10 g of polymer. A medium or... 

A Nylon recycle based on depolymerization via ammonolysis has been shown to be a technically feasible route for the recovery of high purity Nylon intermediates (1-6). In the ammonolysis process, the secondary amides of the Nylon (-6 and / or -6,6) fibers/polymers react with ammonia to break the Nylon chain and form a primary amide and an amine (Figure 1). The primary amide can subsequently be dehydrated to form a nitrile group. The net result is that the ammonolysis product is predominantly a mixture of four major components. 

The molecular arrangement within the crystal units cells of nylon is governed by the need to maximize hydrogen bonding between adjacent chains. Hydrogen bonding within crystallites is facilitated by the fact that nylon chains adopt planar zig-zag conformations with dipoles perpendicular to the chain axis to thin the plane of the molecule. Examples of nylon crystallite structures are shown in Figs. 23.8 and 23.9 for nylon 6 and nylon 66, respectively. In the... 

Why would the number of amide groups in a nylon chain affect the melting point of the crystallites ... 

The cross-sectional shapes of Nylon chains have oxygen and nitrogen atoms protruding so they are less symmetric than polyethylene chains. Along with... 

H. K. Hall (3) of DuPont subsequently proposed an identical mechanism which was published in December, 1958. The mechanism was tested by the simple procedure of adding a pre-formed acyllactam to caprolactam containing sodium caprolactam at 160°C. Very rapid polymerization and a solid nylon casting resulted in four to five minutes. In the absence of the acyllactam initiator, polymerization did not occur. The mechanism for the acyllactam initiated caprolactam polymerization shown in Figure 2 produces a nylon chain with an acylamino end group and without the amino end group of Figure 1. 

Ultraviolet radiation Polyolefins, nylon. Chain scission of surface... 

The nylon-clay nanocomposites were prepared by in situ polymerization in the presence of organically modified, with aminolauric acid, montmorillonite. The reaction between nylon monomer and modified montmorillonite rendered nylon chains end-tethered though aminolauric acid to the silicate surface leading to exfoliated silicates (61). However, not all polymer nanocomposite systems could be produced via in situ polymerization processes because of the chemical sensitivity of polymerization catalysts. Direct melt blending of hydrophilic polymers with montmorillonite in its pristine state or polymers with surfactant-intercalated montmorillonite was found to be possible to deliver polymer intercalated or exfoliated nanocomposites (62,63). 

The development ofand new trends in the determination of molecular weights and molecular weight distribution of aliphatic unsubstituted linear polyamides (nylons) are reviewed here. Critically discussed are intrinsic viscosity - molecular weight relationships and the conformational regidity of nylon chains. Attention is also given to some peculiarities in the behavior of nylons in multicomponent solvents. 

In such a case, podtively dunged groups along the nylon chain repel eadh other, thus expanding the polymer coil. The amcentration of countericms A which... 

It is probable that the equilibrium between the two forms is displaced in favor of ffie cis form with increasing temperature, which has as a consequence shortening of the nylon chain. The negative value of the temperature coefficient is in accordance with such a view. On the other hand, no temperature dependence of unperturbed dimensions was observed in a solution of njdon 6.6 in 85 wt.-% HCOOH by other authors... 

Further, in the case of nylon it has been shown [103] that the presence of metal halides, too, does not alter the shape and position of the master curve, as can be seen from Fig. 4.45. Metal halides cannot be termed as fillers or diluents because their effects are much more pronounced than those expected of fillers or diluents. In fact, they could be better described as reactive additives because of their capability of interacting with the active amide-group sites along the nylon chain. Thus, it is obvious that any changes that occur in the rheological characteristics of the polymer due to the addition of reactive or inert fillers/ diluents are implicitly reflected in the MFI value as well. 

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