INVESTIGATION OF THE STRUCTURE AND THERMOPHYSICAL PROPERTIES OF CROSSLINKED POSS-CONTAINING POLYURETHANES

Abstract

One of the promising scientific directions is the creation of hybrid organo-inorganic materials. This expands greatly the range of properties that are required for modern technological requirements. The biggest obstacle in creating such materials is the complexity of ensuring the uniform distribution of the phase of different nature because of their thermodynamically incompatible. Therefore, in recent days there is considerable interest in hybrid organo-inorganic materials, in which one of the phases has nanoscale. This allows to combine the properties of the organic and inorganic phase at the molecular level. This method leads to increasing of rigidity and strength of materials, their protective properties are improved, the level of conductivity of electric current increases or their cost is simply reduced.Research in the direction of the creation of nanostructured hybrid organo-inorganic systems and nanocomposites received a new impetus in the appearance of polydal oligomeric syssquioxanes (POSS). Due to the possibility of injecting polydrug nucleus of silscvioxanes to side groups of various nature, it is possible to regulate the degree of affinity of sialsecvioxanes with a polymeric matrix and to program the structure and properties of hybrid materials at the nanoscale. Also, due to such features of POSS it is possible to receive hybrid materials on their basis with different morphologies: linear, branched, cross-linked and star-shaped systems.Among the silicon-containing substances, POSS occupy an intermediate position between siloxanes and silicates. On the other hand they can be attributed to spherical siloxanes because they consist from polyhedral structures that are morphologically equivalent to the sphere. Due to the presence of functional groups it is possible to rid the significant lack of siloxanes (not form fibers and films) because of their low intermolecular interaction. Syscvioxanes can be processed at lower temperatures, both in pure form and in mixtures, and also they do not contain traces of metals. Systems based on polymers and POSS have synergistic properties (they are capable of self-rganization). The ability to self-organize of the systems on the basis of the POSS is very important. It allows to receive organo-inorganic materials with a more perfect structural hierarchy . In this work it were synthesized cross-linked hybrid organo-inorganic systems, which can be further used to obtain proton-conducting membranes of hydrogen engines.The method of X-rays scattering in large corners and the method of differential scanning calorimetry (DSC) were used to study the structure of the obtained materials. It was established that the general amorphism of the fine structure of the investigated PU is due to the ability of the mixture of oligosilvesquioxanes to decrease the density of the polymer matrix, and the insignificant ability of the mixture of POCs to create crystals and crystallites.