SETTING THE DIFFUSION PARAMETERS AND MASSTRANSFER OF MOISTURE TO WOOD BY POLYMERIC MATERIAL

Abstract

natural building materials, wood polymer products, thermal insulation products, moisture resistance, performance properties.

The operational reliability and durability of a wood-polymer product depends mainly on the quality and reactivity of the polymer agent, as well as on the class of operating conditions of the object where these materials are used. Over time, the durability of operation may decrease, because the processes of water absorption by wood occur, which leads to swelling and hollowing of the wood-polymer product, and over time its destruction. Therefore, the establishment of the diffusion and mass transfer of water in a wood-polymer material is relevant for establishing the scope of application of such products, which necessitated the need for research in this direction. The paper investigated the resistance of wood-polymer composites to water absorption made from wood sawdust formed on the basis of starch, PVA glue and polymerized with mixtures of polyester and epoxy resins. A method for deriving the diffusion coefficient is proposed, which is based on the analytical solution of the differential equation of mass transfer, which allows, with a slight complexity than numerical ones, to find concentration flows at the boundary of the hydrophobic shell from the coefficients of the original equation and the conditions of uniqueness. It is proved that the main regulator of resistance to moisture absorption is the nature of the binders and the density and porosity of the material. As a result of the tests, it was found that the use of a binder based on PVA glue reduces the process of moisture diffusion to the product by more than 100 times, and for products based on epoxy polymer resin by more than 800 times. Therefore, the wood-polymer material, which was formed on the basis of synthetic resins, is not capable of absorbing moisture and withstands temperature and humidity fluctuations,

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