Jiří Brožek

Molecular Structure of the Complex of Hexano-6-lactam with Magnesium Bromide

A complex of hexano-6-lactam (e-caprolaclam, CL) with magnesium bromide was synthesized. The complex was characterized by IR and NMR spectroscopy, and thermal analysis (TGA and DSC). Based on interpretations of NMR and vibrational spectra and quantum mechanical calculations, the molecular structure MgBr 2 -CL 6 with almost exactly equivalent positions of all six lactam molecules is proposed.

Polymerization of lactams: 70. Anionic polymerization of 2-pyrrolidone accelerated with N-iminolactams

SummaryA pronounced acceleration of the anionic polymerization of 2-pyrrolidone (PD) occurs with the following N-iminolactams: 1-(1-pyrrolin-2-yl)-2-pyrrolidone (PDPD), 1-(1-azacyclohept-1-en-2-yl)-2-pyrrolidone (CLPD), and 1-(1-azacyclohept-1--en-2-yl)-1-aza-2-oxocycloheptane (CLCL). This acceleration effect on the anionic polymerization of PD initiated with 2-oxo-1-pyrrolidinylpotassium decreases in the sequence CLPD> PDPD > CLCL. The possible role of N-iminolactams in the system is discussed.

POLYAMIDE/POLYESTERAMIDE BASED NANOFIBERS

The formation of novel high aspect ratio nanofibers from polyesteramides based on e-caprolactam and e-caprolactone is reported. Nanofibers were prepared by the electrospinning method from polymer solution. Scanning electron microscopy images of nanofiber layers revealed that the diameter of fibers depended on the nature of the solvent or the mixture of solvents used and especially on the composition of polyesteramides.

Synthesis, characterisation and properties of magnesium di(ε-caprolactamate)

Abstract The various synthetic routes to the magnesium di(e-caprolactamate), CL2Mg, were investigated, primarily to establish reproducibility of the route and purity of the products. The reactions of e-caprolactam, CL, with diethylmagnesium, Et2Mg, in diethyl ether have proved to be the most favourable preparative method. The products, primarily CL2Mg and CLnMg, the later representing CL2Mg solvated with (n−2) CL, were characterised by IR, Raman, mass and NMR spectroscopies, including methods of thermal analysis (TGA and DSC), and colligative properties of their benzene solutions were studied as well. A particular attention was paid to the reactions of the products with water.

Ethyl magnesium bromide as an efficient anionic initiator for controlled polymerization of ε-caprolactone

The ring-opening polymerization of ε-caprolactone initiated by ethyl magnesium bromide was studied. Because ring-opening polymerization is extremely fast in the monomer phase, we focused on solution polymerization in toluene. The solution polymerization of ε-caprolactone was characterized by the linear dependence of degree of conversion on polymerization time, which we described by a first-order kinetic equation. The molar mass, determined by SEC using a light scattering detector, was in agreement with that calculated from the degree of conversion attained and the ratio of ε-caprolactone to ethyl magnesium bromide. On this basis, we propose a mechanism for the effect of ethyl magnesium bromide on ε-caprolactone polymerization and provide evidence for this mechanism by isolating a novel stable complex of magnesium bromide with ε-caprolactone.