Лесотехнически Университет

Резюме

The aim of this study was to determine the glue joint shear strength of thermally modified pine (Pinus silvestris) and birch (Betula pendula) in comparison with the unmodified wood and to look at the possibilities of its simultaneous gluing on the same equipment in the same conditions. For the experiments used two types of glue: polyvinylacetate glue (PVAc) Kleiberit 303.0 and polyurethane glue Kleiberit PUR – 501.0. Afterwards glue joint ultimate strength in shear parallel to the grain was measured.

Резюме

In this article described research of physical and mechanical properties of some wood species, that were heat treated through Russian thermoconvective timber dryer (temperature up to 185 ºС) in comparison with untreated wood. Afterwards, moisture content, density, shrinkage, swelling, ultimate strength in compression parallel the grain, static bending strength, impact bending strength, static hardness, moisture absorption, water absorption of the specimens were measured and compared to the properties of untreated wood.

Резюме

Thermally modified wood is a unique natural material with special properties, that have been received after heat treatment of natural wood. All these properties are the result of changes in the chemical composition and structure of the wood. The paper aims to identify gaps in the structure of natural and thermally modified wood. The changes in the structure of the wood after its heat treatment were discussed.

We examined the specimens of pine, spruce, summer oak, hornbeam and birch wood. Microscopic preparations were made from the wood specimens before and after heat treatment. The three main sections of wood at different zoom were observed. There have been noticed differences in the construction of anatomical elements.