Polyamides containing

Fig. 3. Alignment of amide dipoles in polyamide crystals (a) for a two-dimensional array of an odd nylon, nylon-7, (b) for a one-dimensional array of an odd—odd nylon, nylon-5,7 (c) for one-dimensional arrays of polyamides containing even segments an even nylon, nylon-6 an even—even nylon, nylon-6,6 ...

Finally, when polyamides containing four or five carbon diacids, ie, succinic acid [110-15-6] and glutaric acid [110-94-1], respectively, are heated, they form cychc imides that cap the amine ends and prevent high molecular weights from being achieved (84). For nylon-x,4, n = 1 and for nylon-x,5, n = 2. 

Reactive Polyamide Resins. Another significant commercial appHcation of dimer acids is in reactive polyamide resins. These are formed by the reaction of dimer acids with polyamines such as diethylenetriamine to form polyamides containing reactive secondary amine groups (see DiAMlNES AND HIGHER AMINES, aliphatic). In contrast to nonreactive polyamides, these materials are generally Hquids at 25°C. 

The amino acid 58 was used in the solid-phase synthesis of sequence-specific DNA binding polyamides containing N-methylimidazole and N-methylpyrrole amino acids <96JACS6141> and it was also reported that the imidazole-acridine conjugate 59 could effectively catalyze the cleavage of t-RNA <96TL4417>. 

Recall that for a 2 1 polyamide DNA complex a subsef of pairing mles Im//9 or Py//9 pairs can substitute, in certain cases, for Im/Py or Py/Py pairs, respectively [36]. The incorporation of y9-alanine allows a broader set of sequences to be targeted with high affinity. However, the extra flexibility of polyamides containing internal y9-alanines allows both 2 1 and 1 1 hgand DNA stoichiometries in the mi-... 

Fig. 3.8 Variations to solid phase synthesis of polyamides. Use of Fmoc monomers on jS-Ala-Wang resin (left) provides polyamides containing a jS-alanine residue near the C-ter-mini. Polyamides synthesized on the Kaiser...

Baird, E.E. and P.B. Dervan. Solid phase synthesis of polyamides containing imidazole and pyrrole amino acids./. 

WvRTZ, N.R., J.M. Turner, E.E. Baird, and P. B. Dervan. Fmoc solid phase synthesis of polyamides containing pyrrole and imidazole amino acids. Org. Lett. 2001, 3, 1201-1203. 

Polyimidazolinones via Thermal Cyclodehydration of Polyamides Containing ceAmino Acid Units... 

Polyamides containing a-aminoacid units are readily obtained by reaction of bisazlactones (2-oxazolin-5-ones) with diamines. When polyamines such as diethylenetriamine (DETA) or triethylenetetramine (TETA) are used as the diamine component, the resultant polyamides readily cyclodehydrate above 200°C to produce polymers containing 2-imidazolin-5-one units in the backbone. Polyamides derived from simple diamines (e.g. 1,6-hexanedi amine) cyclodehydrate only in the presence of a suitable catalyst. Carboxylate salts and certain Lewis acids have been found to be efficient catalysts for this transformation. 

Polyamides containing /j-aminoamide linkages have been... 

In summary, the preparation of polyimidazolinones from polyamides containing a-aminoacid units (3, X = NH) can now be considered to be a general reaction provided that Rz and/or R3 are not hydrogen. When the polyamide has additional secondary or tertiary amine functionality in the backbone, cyclodehydration appears to be exceptionally facile. In the absence of amine functionality however, a catalyst is necessary to promote cyclization. Further studies of this new heterocyclic polymer system are ongoing in our laboratories. 

Polyamides containing thymine photodimer units in the main chain (17a,b) were prepared by polycondensation of thymine photodimer derivatives (15a,b), which were obtained by the photochemical reaction of the monomeric compound, and various diamines by the activated ester method (Figures 4 and 5) (17, 19). 

Figure 4. Isomers of polyamides containing thymine photodimer.

The photosensitivity tests were carried out only for the polyamides containing different isomers of thymine photodimers to determine the effect of isomer structure on photosensitivity. 

Polyamides containing thymine photodimer units in the main chains showed excellent resolution values (0.3 p m) and behaved as positive photoresists. It is concluded that polymers containing pyrimidine bases displayed high resolution and high sensitivity when used in both negative and positive photoresists formulations. 

Table 2.2 shows two common polymers that are formed by condensation. Notice that DacronT", a polyester, contains ester linkages between monomers. Nylon-6, a polyamide, contains amide linkages between monomers. 

By contrast, membranes U-1, A-2 and X-2 are all chlorine sensitive, each responding in a unique manner. U-1 is a thin film composite membrane, the active layer consisting of cross-linked poly(ether/urea) polymer. A-2 is a homogeneous aromatic polyamide containing certain polyelectrolyte groups. X-2 is a thin film composite membrane of proprietary composition. 

A telechelic polystyrene containing two carboxyl groups at one end of a polymer can be used as a macromonomer in a step polymerization with a diol or diamine to yield a polyester or polyamide containing graft chains of polystyrene. The required telechelic polymer is obtained by radical polymerization of styrene in the presence of 2-mercaptosuccinic acid. 

Polyamides and poljmrethanes have been the carbohydrate-based polymers most widely studied. The preparation of hydrophilic nylon-type polyamides containing... 

A new class of polyamides containing dibenzo 18-crown-6-moieties and alkaline units in the main chain shows [75] varying complexing capabilities with 4-toluene sulfonates of Rb+, K+, Na+ and potassium salts of CH3C6H4SOj, SCNI-, Br-. The polyamide polycondensates are obtained from cis- or trans-4,4 -diaminodibenzo 18-crown-6-(DAC) and a 4,4 -diearboxy-a, cu-diphenoxy-alkane (DCA) (Fig. 25). 

However, if there is a lower enetgy decomposition pathway available, then an alternative degradation reaction dominates. There is a growing body of evidence to suggest that cydization reactions to form small stable ring compounds are one such decomposition pathway, especially for polyamides containing monomers with four to six carbon atoms (77,78) (eq. 7). The first example of this is the formation of cyclic amines, which is the principal decomposition pathway in nylon-4,6 (in eq. 7, n = 1 and R = H) (79) this has also been observed in MPMD-containing polyamides (in eq. 7, n = 2,... 

Wang, J., Mechanism of flame retardancy in polyamides containing magnesium hydroxide, Ph.D. thesis, Brunei University, London, U.K., 1994. 

This anhydrous zinc borate is recommended for use in engineering plastics processed at temperatures higher than 300°C which is the upper limit of Firebrake ZB processing temperature. It is reported to be an effective smoke suppressant in chlorofluoropolymers for plenum cable applications.66 Recently it was claimed that this anhydrous zinc borate can replace antimony oxide (or sodium antimonate) completely in high temperature polyamide applications. Like its hydrated analog, this anhydrous zinc borate can also improve CTI, thermal stability, and the color stability of polyamide containing halogen sources.67 68... 

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