Author: Zhivko Georgiev
Articles
- RESEARCH OF WATER VAPOUR ADSORPTION OF THERMALLY MODIFIED BEECH, SPRUCE AND POPLAR WOOD
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Summary
For use in this search, was realized thermally treatment by temperature 210ºC on spruce, beech and poplar wood in sunflower oil and glycerol environment. Thermally treated wood have some differences from natural, like colour, odor, density and other physical and mechanical properties. From this wood was produced samples with measure 30х30х10mm (last one in longitudinal direction). In parallel with this was produced control samples from same wood dried to constant weight by temperature 102±3ºC. It was determinate water vapour adsorption of samples according to BDS 16987-89.
Keywords: wood, spruce, beech, poplar, water vapour adsorption, thermally modified wood
- INFLUENCE OF WATER-THERMAL CYCLIC TREATED ON THE ADHESION OF PROTECTIVE COATS, FORMED ON WOOD
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Summary
Wood outdoor exposed in normal atmospheric condition affect the colour and texture due to the impact of UV spectrum of light. Although UV rays penetrate into the wood to a depth of not more than 75–100 µm, they are main cause for initiation of weathering it, due to the conduct of complex and physical- chemical processes. As a result of the combined effects of climatic factors, significant structural changes occur in the surface layer (surface erosion). These changes are denoted by the term weathering. This is impact on the aesthetic appearance of the product and the quality of protective coatings. The water plays an important role for wood destruction. The weathering could be minimizing with surface treatment. These treatments can be performed both with soaking up funds forming protective and decorative coatings. The function of these coatings is to receive and minimize external impact and thus extended to life of articles, therefore increase their durability. It is perform an analysis of adhesion of protective and decorative coatings, formed on building wooden products, water-thermal cyclic treated. It is established that the adhesion decrease after water-thermal treating. It is establish that the water penetrates through to the coats distort its adhesion to wood surfaces. It is made recommendation about the conduct of appropriate activities for coating refresh.
Keywords: wood elements, protective coats, building products; water-thermal treatment
- METHODS OF FORMING COATS WITH ANTIQUE EFFECT
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Summary
Methods of finishing for creating antique effects were analyzed. It was established that to create these finishes - chemical stains, patina powder, sealer and top-coats are used. It is easy and quick to achieve these effects, when they are formed on tannin-containing wood. It is established that antique effects can be coated on wood which doesn’t contain tannin (Spruce, Scots Pine), if the effects are made by suitable stains, paints and top-coats. It was made technologies for making „multicolored chestnut“, „antique paint“ and „crackle“ effects on chestnut and ash wood. These special effects are in use in modern fluency in furniture with antique effects. The most important qualities were explored.
Keywords: wood, chemical stains, old finishes, furniture with antique effect
- DURABILITY OF PROTECTIVE DECORATIVE COATINGS FORMED ON THERMALLY MODIFIED WOOD PANELS
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Summary
The durability of polymer coatings, formed on thermally modified spruce wood articles outdoor exposed was investigated. It was applied two regular coating systems (alkyd system; waterborne acrylate system). It was made some marks on destructions in wood and coating during four year outdoor exploitation. It is discover that after four years exploitation waterborne acrylate protection have a local destruction in crater form in the beginning and totally removed in these zone after, while alkyd system is practically destructed in zone near to end. Thermally modified wood without coating become grayish and cracked in the ends. This tendency is also valid for alkyd protection, but not really valid for waterborne acrylate. The coatings do it with alkyd system protection has character destruction in zone of summer timber, which is more underlined for tangential samples.
Keywords: thermally modified spruce wood, alkyd coatings, acrylate coating, coating destruction