Polyamides and Related Polymers

Polyamides, polyesters, and related polymers have been the subjects of several papers on chemical modification and grafting. 

Polyesters and polyamides carrying photosensitive cinnamoyl groups have been synthesized. The original polymers contained either epoxide or olefinic groups in the main chain. These were subjected to ring-opening or a combination of hydro- 

A kinetic study on the hydrolysis, acetylation, and deamination of polyamides in 3-cresol solution has been described. First-order rate coefficients and apparent energies of activations of these reactions indicate two distinct reaction regions, an initial fast region followed by a slow one. A two-phase microfibrillar structure for the polymer in solution is proposed to explain these observations. Preswollen nylon-6 fibres can be crosslinked with bifunctional acetoxy- and ethoxy-organo-silanes in anhydrous conditions. The SiOAc and SiOEt functions react with terminal amino and carboxyl groups on the polyamide, and also at a number of amide links.  

Acrylamide has also been grafted to nylon-6 with Mn compounds as initiators. The reaction is obscure but radical generation on amide nitrogen atoms has been postulated as the initiation step.  

4-chloro-2,6-bis(hydroxymethyl)phenol and 4-chlorophenol, was completely dehalogenated in the first step of the modification. The Fries rearrangement, catalysed by AICI3, was also apparently free from side reactions. 

For the purposes of this chapter, polyamides are defined as polymers which contain recurring amide groups (—CO-NH—) in the main polymer chain. 

The most important commercial polymers of this type are synthetic linear aliphatic polyamides which are capable of fibVe formation these polymers are very commonly termed nylons. It may be noted that by far the greater part of the total output of nylons is used for fibre production but the materials have also become of some importance in non-fibrous applications, particularly engineering applications. 

There are also available more complex synthetic aliphatic polyamides which are not fibre-forming but which have found use in such applications as adhesives and coatings. These products are known as fatty polyamides and are not generally regarded as nylons. 

Various synthetic aromatic polyamides and derivatives have been prepared, principally for evaluation in high temperature applications. Some of these materials have found limited commercial use and are described in this chapter. 

Finally, a very important class of polyamides consists of the naturally-occurring proteins. The importance of proteins extends beyond their various fundamental roles in living matter to several technological applications such as adhesives and fibres. These applications are reviewed briefly in this chapter. 

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Gonsalves K.E., Mungara P.M., Synthesis and properties of degradable polyamides and related polymers. Trends Polym. Sci., 4, 1996, 25-31. 

POLYAMIDES AND RELATED POLYMERS catalyst, e.g., citric acid ... 

POLYAMIDES AND RELATED POLYMERS 199 Table 9.3. Aminoacids found in the hydrolyzates of some proteins [8]. ... 

Table 4 Block and Segmented Polyamides and Related Polymers by Oligomer Combination Reactions ... 

Radiation-induced Degradation.—There have been several reports on radiation effects in polymers,288 including single crystals,287 fluoropolymers,288 polyamides,289 polysiloxanes,270 polyethylene and its copolymers,271 polypropylene,272 polyolefins,273 polystyrene and its copolymers,274 poly(vinyl chloride) and related polymers,275 rubbers,278 polysulphones and other sulphur-containing polymers,277 polycarbonate,278 nylon,279 poly(vinylpyridines),280 and wool.281... 

New Palladium- and Nickel-Catalyzed Polycondensations for Synthesis of Carbon-Carbon Chain Polymers, Polyamides, and Related Condensation Polymers. 

Studies of polymers containing C2-carbaboranyl groups include some based on polyarylacetylenes,47a polyamides and related compounds,47b-d copolymer of acryloferrocene and... 

Figure 5.11 Calculated degree of polycondensation related to the axis of PET chips, shown as axial profiles for a cylindrical particle T, 220 °C hydraulic diameter (dh). 2.9 mm [12b]. From Weger, F., Solid-state postcondensation of polyesters and polyamides, presentation given at the Frankl and Thomas Polymer Seminar, 16 June, 1994, Greenville, SC, USA, and reproduced with permission of EMS Inventa-Fischer, GmbH Co. KG...

Detailed kinetic schemes have also been proposed for many other polymers and the work of Bockhom et al.6-8 is representative of this large area of the literature for schemes relating to polyamide 6, PP, PE, and other polymers. Other experimental approaches, mainly aimed at identifying Arrhenius parameters in similar schemes, are discussed by Howell,9 Lehrle et al.,10 Shyichuk,11 Wilkie,12 and Holland and Hay.1314... 

Although the initial calibration is actually in terms of the relation between [rjl and Mw or M , as described, Eq. (3-44) can only be used to estimate My, for unknown polymers. It cannot be employed to estimate M , (or as the case may be) for such samples unle.ss the unknown is also a fraction with a molecular weight distribution very similar to those of the calibration samples. An important class of polymers which constitutes an exception to this restriction consists of linear polyamides and polyesters polymerized under equilibrium conditions (Chapter 5). In these cases the molecular weight distributions are always random (Section 5.4.3) and the relation... 

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