Polylactam

Among the more common thermoplastics from ring opening polymerization of interest in composite processing are polylactams, polyethers, polyacetals, and polycycloolefins. It has also been shown that polycarbonates can be produced from cyclic carbonates [22], Anionic ring opening polymerization of caprolactam to nylon 6 is uniquely suited to form a thermoplastic matrix for fiber-reinforced composites, specifically by the reaction injection pultrusion process [23-25]. The fast reaction kinetics with no by-products and the crystalline... 

Macrocyclic polycarbonyls are cyclic ligands containing carbonyl functionalities. Several categories come under this heading the macrocyclic oligoketones (7), the polylactones (8) and the polylactams (9). 

Estimate the limiting value of Tg for polylactams (aliphatic polyamides) at increasing number of CH2 groups in the chain. 

Polyoxa macrocycles, known more commonly as the crown ethers, comprise an extensive area of research, with a repertoire of types and variations. Some of these macrocycles have been utilized predominantly for purposes other than metal ion complexation, and these will not be discussed in depth in this review. Included in this latter category are the polycarbonyls, polylactones,polylactams and carcerands. " ... 

A new macrocyclic polylactam-type neutral receptor for anions - structural aspects of anion recognition, A. Szumna and J. Jurczak, Eur. J. Org. Chem., 2001, 4031. 

Synthetic or man-made, e.g., PVAl, CA, polylactams e.g., polycaprolactam), polyglycols (e.g., polyethylene glycol), poly(aspartic acid), poly(butylene succinate-co-adipate), as well as poly(3-hydroxy butyrate) or PHB, poly(P-hydroxybutyric acid) or PHBA, poly(hydroxy-valerate) or PHV, poly(lactic acid) or PLA, polyCglycolic acid), polyglycolides, polybu-tyric acid, their copolymers and mixtures. 

Figure 5.8 shows the pyrogram of (a) nylon 6 and (b) nylon 6/6 observed by nsing a glass capillary separation colunm. The main pyrolysis products in (a) are 8-caprolactam" " and small amounts of nitriles (MN and MN(A)). Polylactams consisting of relatively short methylene chains, such as nylon 4 and 6, tend to regenerate the associated monomeric lactame upon heating. 

The minor peaks of saturated MNs are always accompanied by those of the oleflnic MNs. In addition, the smaller MNs and the associated hydrocarbons (HCs) are formed through the further C-C bond cleavages. The main degradation pathway is basically the same for the polylactams, including relatively longer methylene... 

Thermal degradation of various aliphatic polyamides was also studied by Py-EIMS, Py-field ionization (FI), and field desorption (FD)-MS. The Py-EIMS studies demonstrated that the polylactams mainly decomposed to cyclic oligomers, whereas the favored decomposition pathways of diamine-dicarboxylic acid-type polyamides were the cis elimination reaction and the cleavage of the amide bond, which also occurred in the polylactams with a large number of methylene groups, such as nylon 12. On the other hand, Py-FIMS of various diamine-dicar-... 

Nitrogen-containing polymers The polyamide ny-lon-6 has been discussed above. Other polylactams behave similarly and display a characteristic pair of peaks at [2M-I-H] and [2M —OH]" ". Diacid-diamine polyamides, (RiCONHRiIm, show some similarity to in-chain polyesters having dominant fragments of the type R-C = 0. However, since there is no equivalent of the RCOO ion from nylons, the negative ion spectra are usually lacking in... 

The ions of cobalt(III), rhoditun(III) and iridium(III) are the best templates for assembling octahedral complexes with ligands of the sepulchrate type. To obtain macrocyclic polylactones and polylactams, templates with covalent character bonds, such as Sn, Si, Sb, or B, are used. Copper(I) is the most convenient centre for the synthesis of catenanes. 

A unique approach to the controlled design of such systems as macrocyclic polylactones, polylactams and related compounds has been developed [1]. The synthesis of these substances, called biomimetic macrocyclic molecules by reason of their resemblance to naturally occuring ionophores (such as valinomycin, nonacdn, enniatin and enterobactin [2-5]), is carried out by a covalent-template method. This description arises from the use of elements forming covalent bonds (tin, silicon, antimony, boron) as matrices. 

Organosilicon derivatives can be used for the covalent-template synthesis of macrocyclic polylactams [28, 29]. The method includes conversion of acyclic dia-... 

Macrocyclic poly lactones, polylactams and related compounds 459... 

The production of new macrocyclic systems has become possible due mainly to the development of new template centres for specific ligand products, such as the covalent-template approach to the synthesis of macrocyclic polylactones, polylactams and related compounds. Also of note is the the assembly of the cat-echoylamide systems H6L1019 and H6L1022 on an iron(III). In these situations the specific arrangement of functional groups required for macrocyclisation is a result of complex formation. 

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