|
|
Evaluation of wood surface treatments by non-destructive methods
Plšek, Matěj ; Brožovský, Jiří (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis will be describing the basic technologies of timber processing and macroscopic signs according to which the visual strength grading is performed. Imaging methods will be described to identify the roughness of wood surface. In the experimental part, the surface roughness parameters for various surface treatment methods will be determined and the dependence of the surface roughness on wetting and penetration depth of the adhesive will be monitored.
|
|
| |
|
|
Influence of material base of coating systems onto wood durability
Bednářová, Ilona ; Petránek, Vít (referee) ; Vaněrek, Jan (advisor)
The thesis deals with the influence of the base material of the coating systems for wood durability when we exposed them to external conditions. The theoretical part is devoted to wood durability and weather resistance with a detailed description of the tests the durability of coating systems. A substantial part of the theory is devoted to description binder component of the coating material. In the practical part was performed the experiment, which examined the influence of the thickness of the coating system, the type of coating material (paint or lasure) as well as the type of binder (water dispersion with an alkyd or acrylic resin, respectively solution coating system with the alkyd resin). All coating systems were exposed to natural and artificial durability tests. The criterions for evaluation were chosen differences of colours.
|
|
|
Study of durability of wood glue bonds against increased temperature
Kučera, Vít ; Vejpustek,, Zdeněk (referee) ; Vaněrek, Jan (advisor)
In this time are for design of wooden elements available simplified procedures for fire modeling which defines ČSN EN 1991-1-2. But it is not experimentally tested the impact of adhesive on the final value of fire resistance of laminated panels. This diploma thesis solves basic normative practices that could explain the durability of glue bond against increased temperatures. in the practical part will be undertaken to experimentally assess the impact of various kinds of adhesive-based (epoxy, formaldehyde, PUR and EPI) on the glued bond durability against increased temperature. Glued joints that will be subjected to gradual temperature exposure in order to assemble the dependence of the temperature influence on the final strength of the joint according to the type of adhesive.
|
|
|
Study of the interphase region of wood bonds
Chlup, David ; Dufka, Amos (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis deals with summarizing knowledge on issues related to the penetration depth of the adhesive into the wood structure. In the thesis they are described all adhesion theories. We focus on the effect of viscosity and durability bond line according to varying amounts of filler adhesive. Furthermore, it is described some microscopic techniques, which measure the penetration of the adhesive into the cell structure.
|
|
|
Heat resistance of wood bondlines
Šustáček, Jan ; Melichar, Tomáš (referee) ; Vaněrek, Jan (advisor)
This thesis is focused on studying the impact of elevated temperatures on the resistance of bonded joints. The aim of this study is to assess the impact of exposure to temperatures on selected types of adhesives. In the theoretical part was made research and comparison of selected species agglomerated materials and described the issue of fire safety of buildings. To determine the strength characteristics of bonded joints at different temperatures have been made in the practical part load tests according to valid standards.
|
|
|
Wood microstructure analysis onto the strength parameters
Martinek, Radomír ; Kuklík,, Pavel (referee) ; Vaněrek, Jan (advisor)
This work focuses on a closer examination of the microstructure of wood and the relationship between microscopic and mechanical properties of wood. The main point of the practical part of this study is a measurement of microfibril angle (MFA) in the S2 layer of a wood cell wall. This layer occupies more than 80 % of the total thickness of the cell wall and thus has the greatest influence on the mechanical properties of the wood cells. MFA values as well as values of bulk density show a strong dependence on the modulus of elasticity in the longitudinal direction, as well as on the values of shrinkage. The theoretical part involves methods for measuring MFA, variations of MFA, wood properties evolving from the MFA and also mechanical properties of wood cell walls measured by nanoindentation.
|
|
|
Analysis of filler types onto the wood plastics composites
Blaha, Lukáš ; Pospíšil,, Ladislav (referee) ; Vaněrek, Jan (advisor)
Wood polymer composite (WPC) is a material that combines the wood material and the thermoplastic matrix. As filler to be used as wood flour and thermoplastic matrix will be used in primary or recycled polypropylene. WPC will be made by injection molding. The aim of the thesis is to find the optimal ratio between primary and recycled polymer in which the result will be the best physical and mechanical properties.
|
|
|
Modification of epoxy resin effecting ductility of wood bonds
Hudečková, Petra ; Drochytka, Rostislav (referee) ; Vaněrek, Jan (advisor)
This bachelor thesis is focus on a jointing process of wood parts, the basic kinds of adhesives that are used for wood constructions, and also deals with an important demands on a bonded wood joint. Then there is briefly described an issue of fracture toughness and the ways of epoxy adhesives filling, primarily filling with the rubber, the thermoplastics and other fillers. In the experimental part the reinforcing of epoxy matrix with the different quantity of rubber was carried out. The mixture was prepared by an ultrasound homogenizer. Firstly, the tensile strength test with epoxy samples was carried out. Secondly, the Young modulus was calculated and in the last part the fracture surface was analyzed with the scanning electron microscope.
|
|
| |
guest ::
