Schimmelpilze auf beschichteten Holzfassaden: chemische und physikalische Einflussfaktoren

Volkmer, Thomas (2007). Schimmelpilze auf beschichteten Holzfassaden: chemische und physikalische Einflussfaktoren (Dissertation, Albert-Ludwigs-Universität Freiburg)

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Coated wooden facades underlie during their lifecycle an aging and degradation process. This process is determined by different factors: material porperties, climatic conditions and biological attack of microorganism. The main focus of this thesis was to analyze the colonization of coated wooden facades by mildews and blue stain fungi. The goal was to find correlations between certain chemical and physical parameters and the susceptibility of the surface for colonization by the fungi�s. In this study the different coatings systems were applied, the particular parameters were analyzed and compared with the susceptibility of the surface towards mildews and blue stain fungi�s. The practical work was running over 3 years. The tests were done year wise corresponding to program. After each year there was an optimization of the coating systems (concerning there chemical composition) based on the test results. With this test program two major objectives should be achieved: 1. Determination of general chemical and physical Correlation towards the biological susceptibility of coated wooden facades. 2. Development/optimization of a durable coating system for wooden facades with low biocid content and high resistance against the colonization by mildews The analyzed systems were supplied by the industrial partners and represent the state of the art of wood coating material. The industrial background of this study led to a quite heterogenic variation of the coatings. Because of its economical meaning in middle Europe spruce were used as substrate in the most of the cases. All results are directly connected to the specific coating systems. Small changes in the coating formulation will surly lead to different conclusions. The behavior of the wooden facades should be evaluated with respect to the practical use. That�s why different aging procedures were applied (natural and artificial weathering, artificial pollution of the surface, changing vapor flow). This procedure should show the influence of the climatic parameters towards the biological resistance of the probes. With respect to the physical behavior of the system coating-wood the following topics were investigated:  Mechanics of the coating (hardness, glas-transition-temperature, adhesion, crack development)  Hygroscopic behavior of the system coating-wood (water vapor diffusion, water consumption)  Morphology of the surface (roughness, surface tension, spore adhesion) With the help of nanoparticles in the top coat it was tried to modify the surface properties in order to reduce the susceptibility of the surface towards a microbiological attack. As the main biocid substance IPBC were used and analyzed. The diffusion and degradation process of IPBC in the coating were described and investigated. With the FT-IR technology it was attempted to analyze certain changes in the chemical structure of the surface (biocid degradation, polymerization reactions). The evaluation of the physical and chemical properties was done by the bio tests. The samples were inoculated by a specified number of spores and incubated under different conditions in the laboratory. After 6 weeks of incubation the samples were evaluated following a specified scheme. A weathering test under natural conditions was running parallel and the evaluation of the colonization by fungi�s was done accordingly. Within this study valuable results could be achieved concerning the colonization by mildews of coated wooden facades. Generally it can be pointed out, the extreme conditions during the laboratory tests do not correlate very good with the experiences from the field trials.

Item Type:

Thesis (Dissertation)

Division/Institute:

Architecture, Wood and Civil Engineering
Architecture, Wood and Civil Engineering > Institute for Materials and Wood Technology
BFH Centres > BFH Centre for Wood - Resource and Material

Name:

Volkmer, Thomas

Subjects:

Q Science > Q Science (General)
Q Science > QH Natural history > QH301 Biology
Q Science > QR Microbiology
T Technology > T Technology (General)
T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TH Building construction

Language:

German

Submitter:

Christelle Ganne-Chédeville

Date Deposited:

22 Apr 2020 13:58

Last Modified:

22 Apr 2020 13:58

URI:

https://arbor.bfh.ch/id/eprint/11393

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