Hybrid wood-polymer composites in civil engineering
The interest in wood-based materials and structures is increasing every year, and as a result, attempts are constantly being made to modify it, in order to increase mechanical and operational characteristics. In this case the complicating circumstances are the contradiction between the hydrophilic nature of wood and water repellence of the majority of the thermosets that can significantly affect the properties of wooden parts and structures. The paper analyzes the state of research in this area and draws conclusions in favor of methods of wood gradient impregnation with reinforcing water-compatible epoxy thermosets and external as well as interlayer reinforcement of wood structures with high-strength glass-, basalt-, organo- and carbon-fiber ribbons with anisotropic properties. The possibility of modification of water-compatible epoxy polymers by carbon micro- and nanoparticles of new species was also studied. The results of the pilot studies of the wooden details gradient impregnated with the water compatible epoxy compositions modified by sulfoadducts of nanoclusters of carbon ("Ugleron C") and carbon nanoporous microfibers (CNPMF) are given. The possibility and features of external reinforcing of the wooden details by glass ("Е" – type fibre), carbon (on the basis of carbon fibers) was considered and the case of the basalt and polyaramid unidirectional tapes was estimated. The technology of the additional strengthening the wooden details by an external membrane from a multifunctional composite water compatible coating – the "EpoxyPAN" was offered. Results of the tests the samples of the wooden details covered with a continuous membrane from "EpoxyPAN" have confirmed the previous assumptions of the prospects of such technology. Thus, the possibility of creation of the hybrid wood-polymer composites (HWPC) of new types is proved and problems of further work are formulated.