SVIBOR - Project code: 4-04-031

MINISTRY OF SCIENCE AND TECHNOLOGY

Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69
E-mail: ured@znanost.hr

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Project code: 4-04-031


INVESTIGATION AND IMPROVEMENT OF THE QUALITY OF WOOD PRODUCTS


Main researcher: LJULJKA, BORIS (26183)


Assistants
Type of research: developmental
Duration from: 04/30/91. to 04/30/94.
Papers on project (total): 81
Papers on project quoted in Current Contents: 4
Institution name: Šumarski fakultet, Zagreb (68)
Department/Institute: Department
Address: Svetošimunska 25
City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0)41 21 82 88
Fax: 385 (0)41 21 86 16
Summary: The investigation of the improvement of the quality of wood products has been divided into several autonomous, still interrelated subjects. - Wood drying; the performance analysis of characteristic representatives of pre-dryers and kilns - Modification of the wood surface; gluing surfaces of beech-wood elements could be successfully modified by sanding procedures or by ionized radiation in the presence of air. This enhances the free surface energy and the strength of the glue bond. The best sanding results prior to finishing are obtained by following combinations of grit sizes and sanding directions: 100ş, 150ş, 180ş or 120Á, 150ş, 180ş. The roughness of the surface is not increased as the sanding belt gets blunt. Wood treatment with water stains and oil stains increases the roughness, this being more expressed with water stain than with nitro stain or oil stain. The differences in roughness after staining are greatest on beech, somewhat smaller on pine, and smallest on oak wood surfaces; - Surface layer degradation; thin wood strips exposed to photodegradation exhibit short-term increase followed by further decrease in tensile strength; degradation rates could be monitored by changes in mechanical properties and analysis of the fracture surfaces using scanning electron microscope; - Changes in the wood - adhesive system; the durability of laminated components depends on the structure of the lamellae, thickness of the outer lamella, other design characteristics, type of applied adhesive and the position of the glue line on the cross section. Upright and horizontal frame parts show significant differences in durability; - Other research of the wood products quality; finger jointing is better than tenon and groove jointing for corner joints of panelled doors. Strength and stresses in the mortice and tenon joints were examined experimentally and by computer simulation. - Moisture permeability and heat conductivity are very important parameters of the mattress design; their optimization significantly improves the quality of the mattress.

Keywords: wood drying, wood surface, surface layer, durability of the surface layer, wood glueing, wood finishing, surface modification, wetting angle, sanding, staining, roughness, bed and heat transfer, bed and moisture transfer, laminated wood, corner joints, quality of the product.

Research goals: The quality of wood products depends upon a broad complex ofmaterials, procedures and activities. The research about some ofthose materials, procedures and activities was not sufficient,and that prevented further improvement and development of theproduct quality. Therefore the general aim of the research wasexperimental establishing the factors that influence the qualityand that were not sufficiently examined or scientificallyapproved. The optimization of such factors should lead towardsimprovement and further development of the quality of products. Particular objectives of the project were: - improvement of the quality of wood drying - optimization of gluing procedures by appropriate preparationof the gluing surface (interface) and its modification bymechanical processes, chemical treatments and radiation. In orderto assess the achieved effects, along with the microgeometrymeasurements, new methods for determination of the wood surfaceenergy ought to have been established. - determination of the optimal sanding regimes prior to finishapplication and establishing their dependence on the woodstructure, grit size of the abrasive, combination of abrasivesused for sanding, the directions of sanding in regard to thegrain, bluntness of the abrasive and pretreatment of surface withwater, nitro stain, water stain or oil stain, - investigation of the weathering resistance of the woodsurface layer and possibilities of its improvement by woodmodification - investigation of the durability of laminated wood buildingcomponents depending on their design characteristics and the typeof adhesive - the choice of optimal wood joints for the critical furnituredesign details - investigation and improvement of the bed and mattress designfocusing on the heat transfer, moisture permeability and fire resistance.

COOPERATION - PROJECTS


  1. Name of project: ALIS ZAG 984/241 IMPROVING THE SERVICE LIFE OF EXTERIOR TIMBER BUILDING COMPONENTS
    Name of institution: BUILDING RESEARCH ESTABLISHMENT (TIMBER DIVISION)
    City: WD2 7JR - GARSTON - WATFORD, UNITED KINGDOM

COOPERATION - INSTITUTIONS


  1. Name of institution: EMPA - EIDGENOSSISCHE MATERIALPRFUNGS- UND FORSCHUNGSANSTALT
    Type of institution: University/Faculty
    Type of cooperation: Joint publishing of scientific papers
    City: CH-8600 - DBENDORF, SWITZERLAND

  2. Name of institution: Institut fr Holzforschung, Universit„t Mnchen
    Type of institution: University/Faculty
    Type of cooperation: Systematic exchange of information
    City: 80797 - Mnchen, BRD

  3. Name of institution: TILIACO
    Type of institution: Non-profit
    Type of cooperation: Occasional exchange of information
    City: 10000 - Zagreb, Croatia
Other information about the project.
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