Two methods for the functionalization of single-walled nanotubes were proposed, namely grafting of acyllactam groups or amine-terminated polyimides. Such modification allows for the preparation of stable nonsagging nanotubes dispersions in the melted e-caprolactam. These dispersions were further utilized for in situ ring-opening anionic polymerization of ecaprolactam with e-caprolactam magnesium bromide as a catalyst and N-acetyl-e-caprolactam as an activator. Some unique features of the obtained novel nylon-6/nanotubes composites are significantly increased thermal stability (T 5% up to 400 C), enhanced compression modulus and Izod impact strength of polymer blocks (by 25% and 150%, respectively) and advanced tensile strength and elongation of polymer films. Such an improvement in the properties of the composites in comparison with neat nylon-6 was gained by the addition of as little as 0.1-0.01 wt% of modified nanotubes.

Anionic polymerization of e-caprolactam was performed in the presence of only 5 wt % of aromatic polyimides having five-and six-membered imide cycles and bearing hexafluoroisopropylidene, ether, fluorene, siloxane, phthalide, or SO 3 HA groups, both in the polymer backbone and as side moieties. The synthesized new copolymers were fully characterized by IR spectroscopy, thermomechanical analysis, dilatometry, and X-ray diffraction. Tough and frictional properties of the obtained copolymers were estimated as well. It was found that on the selection of polyimide activator it is possible to gain the desirable control over the polymer properties, namely the gel-fraction content, phase composition, compression modulus, notched Izod impact strength, temperature of frictional contact, friction coefficient, etc. These investigations will facilitate the choice of the optimum macromolecular activator for the modification of both the synthetic method and the properties of the commercial polycaproamide.

A series of the copolyimides have been synthesized by one-step high-temperature method in m-cresol solution to explore their effect on the optical fibre coatings formation and properties. The following parameters that influence the coating quality and properties have been estimated: the viscosity of the polymer solution, drawing technological parameters, polyimide (PI) structure and molecular weight. It was found that copolyimides bearing side hydroxyl and carboxyl groups formulate the coatings with good adhesion without additional coupling agent. The fibres with elaborated PI coatings have high thermal stability. For some of them, 20% reduction of the fibre’s bending strength takes place only after heating for 24–72 h at 300°C.

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D b r i e m e n t d'ktrophysique Relativiste et d e Cosmologie O b m t o i r e , 92190 Meudon, France AbsImacL Slatting from the equations of motion obeyed by fields, as they result from general approximations [they are m!ia to be of the following form [k2n(k)]+ = 0, for quasi bosons, and a similar equation for quasifermions] a lagmgian formalism is derived and, accordingly, consewed quantities are obtained. Next these fields are quantized and general expressions for the main observables are derived. Statistical mechanics of quasiparlicles then follow via the use of covariant Wigner functions.