Nowadays, almost all of the wooden composites are connected with thermos reactive adhesive resins. The commonly used binders are phenolformaldehyde, carbamide-formaldehyde, melamine-formaldehyde and diisocyanate resins. From widespread timber and wood sawdust are made the tiles composite materials, which are obtained from wood flour and binders by hot pressing at 120-1400C. In composites biding agents are urea 1, melamine 2, 3 or phenol-formaldehyde 4,5 resins. By the same composition is characterized today widely used high, medium and low-density fiberboards 6-8, which is composed of phenol-formaldehyde resins that is the class of carcinogenic substances, due to formaldehyde emissions. These materials nowadays have a number of shortcomings, the most important of which is that emissions from these materials contain cancerogenic harmful formaldehyde for the human organism. Ecologically friendly new composite materials with high-technical characteristics are made on the basis of wood sawdust and organic/inorganic binders. These composite materials are obtained on the basis of a new binders phenylethoxysiloxane (PhES-50, PhES-80), liquid glass, polyethylene and colophony (at different pressures and temperatures). The binder used simultaneously acts as both a binder and a reinforcement agent. The surface structure of the new composite materials was studied by means of optical microscopy, Scanning Electron Microscopy and Energy Dispersive X-ray Micro-analysis. For composites tensile strength at bending, impact viscosity, thermogravimetric stability and water absorption coefficient have been examined. Optimal conditions for obtaining new, ecologically friendly composites have been established. The obtained composites are characterized by high mechanical properties, thermal resistance, ecological purity and low water absorption capacity, which is one order of magnitude smaller than the water absorption of existing particle board.
Markarashvili et al. (Thu,) studied this question.