A new technique is described for preparing poly(propylene)-silica nanocomposites with the use of crazing of polymers in reactive liquid media that exhibit an adsorption capacity with respect to the polymer and contain functional groups able to enter into different chemical reactions, in particular, hydrolytic condensation. The advantage of this technique over conventional mixing is that the components can be mutually dispersed at the nanolevel without using additional modifying additives. The hydrolytic condensation of tetraethoxysilane and hyperbranched poly(ethoxysiloxane) in the presence of acid or base catalysts with the formation of a silica gel in a crazed polymer matrix is investigated. It is established that the morphology of the prepared composites is determined by the structure of the crazed polymer matrix, the nature of the precursor, and the hydrolytic polycondensation conditions. Composites are prepared in which the silica phase is located either inside the poly(propylene) matrix (in the form of a continuous phase or discrete particles) or on the surface of the polymer. Porous silicon plates are produced through heat treatment of the poly(propylene)-silicate nanocomposites at a temperature of 700°C.

Изучен крейзинг различных полимеров (ПЭТФ, изотактического ПП и ПЭВП) в средах разветвленного полиэтоксисилоксана и его низкомолекулярного аналога – тетраэтоксисилана. Показано, что сверхразветвленный полиэтоксисилоксан является эффективной ААС для крейзинга твердых полимеров различной природы и создания нанопористых структур с объемной пористостью до 60%. Установлено, что в зависимости от природы полимера возможна реализация двух механизмов крейзинга – классического и делокализованного. Проведены реакции гидролиза (щелочного и кислотного) в порах с образованием твердого кремнезема. Электронно-микроскопическими методами подтверждено, что превращение вязкой адсорбционно-активной жидкости в твердое вещество непосредственно в объеме матрицы способствует стабилизации высокодисперсной структуры полимера, возникающей в процессе крейзинга.

The crazing of various polymers (PET, isotactic PP, and HDPE) in the presence of branched poly(ethoxysiloxane) and its low-molecular-mass analog—tetraethoxysilane—has been studied. The hyperbranched poly(ethoxysiloxane) is shown to be an effective adsorptionally active medium for crazing of various solid polymers and development of nanoporous structures with a volume porosity of up to 60%. Depending on the nature of polymers, two mechanisms of crazing (either classical or delocalized crazing) can take place. The reactions of hydrolysis (basic and acidic) within the pores leading to formation of solid silica have been performed. Electron microscopic observations provide evidence that the transformation of a viscous adsorptionally active liquid into a solid compound directly within the volume of a polymer matrix leads to the stabilization of a highly dispersed polymer structure that arises in the course of crazing.

Block cooligomers of 2,6,7,10,11-pentapentyloxy-3-(3-acryloylpropyloxy)triphenylene and poly( tert -butyl acrylate) have been synthesized by the atom-transfer living radical polymerization. The preformed 3,6,7,10,11-pentapentyloxy-3-(3-acryloylpropyloxy)triphenylene block comprising eight monomer units was used as a macroinitiator with a fixed length, whereas the length of the poly( tert -butyl acrylate) block was varied through a change in the monomer-to-macroinitiator ratio. The microphase separation phenomenon has been established with DSC and X-ray diffraction. However, the sizes of discrete structures observed via transmission electron microscopy and atomic-force microscopy lie in the micron-size length (0.1–3.0 μm). This fact is inconsistent with the molecular characteristics of individual blocks. It is proposed that the micron-sized structural elements are not true domain structures belonging to each phase but reflect the occurrence of aggregation in solution preceding formation of thin films.

A new approach to the preparation of copper-containing polymers based on porous HDPE obtained via the mechanism of solvent crazing is advanced. This approach involves application of ethanolamine, which simultaneously serves as an adsorptionally active medium, a complexing agent, and a reducing agent. The thermochemical decomposition of organometallic compounds allows one to prepare composite materials which are characterized by a high level (up to nanometric) of mutual dispersion of the components and high mechanical characteristics.