β‐Lactams, Their Polymerization and Use as Raw Materials for Fibers

Abstract

β‐Lactams can be prepared by cyclization of β‐aimno acid esters. Recently they have become available also from olefins by addition of N‐carbonysulfamyl chloride (isocyanatosulfonyl chloride) and from aldehydes by reaction with N‐carbonylsulfamyl chloride and ketene. Condensative or anionic polymerization results in polyamides the chains of which contain many more amide groups than the chains of polyamides of the nylon‐6 type. Hence the new polymers resemble silk moreclosely. Fibers and films can be prepared from solution.

Synthesis and characterization of poly(4-alkyl-4-methyl-2-azetidinone)s

“…The X-ray patterns of the other poly(4-alkyl-4-methyl-2-azetidinone)s exhibit only a broad halo of diffusion, as shown in Figure 1(c) for poly(PrMA). These results indicate that the racemic poly(4-alkyl-4-methyl-2-azetidinone)s are semi-crystalline when the alkyl substituent is a methyl or an ethyl group, as observed by Graf et al 3 for poly(4,4-dimethyl-␤-lactam), but are amorphous when it is a propyl, butyl, or pentyl group, in agreement with the results of Bestian. 4 Let's recall that the gels formed during the synthesis of poly(MeMA) and poly(EtMA) were opaque whereas the others were transparent.…”

“…With poly(MeMA) and poly(EtMA), the peak is broader and has a shoulder (indicated by an arrow), as observed on Figure 3 for poly(MeMA), that is attributed to the fusion of the semi-crystalline polymer before decomposition. In addition, the melting temperature of poly(MeMA) at 310°C is in good agreement with that of 296°C obtained by Graf et al 3 for the same polymer; that of poly(EtMA) is of 290°C. The thermogravimetric curves (TGA) of poly(4-alkyl-4-methyl-2-azetidinone)s exhibit a similar shape as that of poly(MeMA), as observed on Figure 3, but they are shifted at higher temperatures with a decrease in the size of the alkyl substituent, as reported on Figure 4.…”

“…H2SO4 at 30°C. However, the intrinsic viscosity of poly(4,4-dimethyl-2-azetidinone) is relatively high, indicating that there was no or little degradation during the solubilization, and molecular weights have been estimated (Table II) using the Mark-Houwinck parameters reported by Graf et al 3 for the same polymer, at 25°C in conc. H2SO4.…”

“…3 The fibers here prepared could not be stretched enough for the recording of satisfactory X-ray fiber diagrams due to the low molecular weight of the polymers. Actually, poly(4,4-disubstituted-␤-lactam) fibers obtained by Graf et al 3 had an intrinsic viscosity at least twice higher e Molecular weight determined from the viscosimetric data, using the Mark-Houwinck parameters reported for poly(4,4-dimethyl-2-azetidinone) at 25°C in concentrated H 2 SO 4 3 . f Molecular weight expected from the molar ratio of the consumed monomer to the activator.…”

“…2 For example, Graf et al, 3 Bestian, 4 and Schmidt 5 studied the polymerization of a series of mono-, bi-, triand tetra-substituted 2-azetidinones, and the properties of the resulting polymers. Their chemical resistance and melting temperature depend on the chain stereoregularity and the nature of the substituents.…”