Wood and lignocellulosic materials for building applications

Subject description

Wood and other lignocellulosic materials are daily exposed to biotic and abiotic factors of degradation. Biotic degradation, primarily wood decay fungi will be elucidted. In the next step biocidal and non-biocidal techniques for wood protection will be outlined. Great emphasis will be on the modification of wood (physico-chemical, chemical passive and active and chemical surface modifications), the protection of wood with hydrophobic systems (waxes, wax emulsions, oils, silanes, siloxanes …) protection by construction and the appropriate selection and use of wood species and of different lignocellulosic based composites. Students learn the importance of water and sorption properties for the fungal growth and development and methods for determination of the water exclusion efficacy, as well as its impact on load bearing capacity of different lignocellulosic based composites. Attendees will learn about methods for evaluating the service life of the wood and wooden materials, the influence of climate on life expectancy and methods for its estimation. We will describe the dose-response model, and apply it on the practical example.

Students are going to learn the significance and role of different wood based composites in construction, whereby their role is going to be divided into five segments; sorption, mechanical insulation (thermal and acoustic), fire resistance and façade system. In all cases students are going to learn the behaviour of material due multiple effect of different factors, whereby they are going to get familiar with different predictional models for the behaviour of wood based composites for retaining their basic function in construction. The emphasize is going to be focused on critical conditions for load failure of construction, degradation of properties due change in moisture, development of different microorganisms and mould, etc. They are also going to learn about the possibility for improvement of different properties by use of different nano biomaterials. Students will also learn about the impact of wood based composites on the living environment. Some possibilities of recycling of wood and wood based composites from old (demolished) objects are going to be presented. Students will learn properties development (changes) of wood based composites during their usage (long term behaviour), prediction possibilities and non-destructive test methods for the tracking of composites properties.

Weathering of lignocellulosic materials, wood-based composites and of wood (recapitulation of some basic information). Detailed survey of photodegradation processes in lignocellulosic materials and a short overview of the most appropriate experimental techniques to follow these processes (SEM; FT-IR, EPR). Contemporary protective exterior coatings. Novelties in development of UV absorbers, free radical scavengers and nanoparticles for protection of a substrate and of a surface finish. Superhydrophobic surfaces. Self-cleaning surfaces. TiO2 nanoparticles for protection against UV light (rutile); photocatalytic activity of TiO2 in self-cleaning surfaces (anatase).

The subject is taught in programs

Objectives and competences

Objectives: to recognize the importance and mechanisms of the biotic factors of degradation. This will enable understanding of the mode of action of the biocidal and non-biocidal methods for protection of wood and similar materials. Students understand and recognize the importance of water in the wood for the fungal development and understand technical solutions how to keep the wood dry. Understanding of the materials and basic physiology of fungi enables the design and evaluation of the service life of the wood. They are able to select the appropriate wood or wood-based material for each use and predict its service life.

Students will learn and understand the role of wood based composites in construction. They understand the ageing process on the properties of wood based composites. Students will learn and understand different prediction systems of behaviour of composites in longer time of use. They learn about the possibility of use of different biomaterials as reinforcement for wood based composites. Students will also learn about the different methods for tracking of properties of installed(used) composites.

Students learn and understand photodegradation processes of lignocellulosic materials and experimental techniques to follow these processes. A student learns new findings in development of UV protective compounds, with a focus on applications of nanoparticles in protection of wood against weathering. He/she learns superhydrophobic and self-cleaning surfaces and understands how to achieve superhydrophobic and self-cleaning effects. In addition, he/she gets known with rutile TiO2 nanoparticles for UV protection and in TiO2 the form of anatase for self-cleaning surfaces.

Competences:

The acquired knowledge allows a participant to understand the most important novel weathering-protective materials and to be capable to make the most optimal selection of contemporary protective means for lignocellulosic materials in various constructions and objects that are exposed to weathering and biotic factors of the decay.

Gain knowledge will enable the student to select appropriate composite with regard to the load/exposure from the aspect of whished service lifetime and to track the behaviour of material in construction.

Teaching and learning methods

Lectures (20 h)

Seminar (15 h)

Laboratory work (40 h)

Other (15 h)

Expected study results

Knowledge and understanding:

Knowledge and understanding:

Students understands the mode of fungal degradation and the importance of water in wood. They are familiar with different techniques for wood protection, their advantages in disadvantages. They understand how to select proper wood species, proper treatment and design its use for various building applications.

Students will learn and understand the role of wood based composites in construction. They understand the ageing process on the properties of wood based composites. Students will learn and understand different prediction systems of behaviour of composites in longer time of use. They learn about the possibility of use of different biomaterials as reinforcement for wood based composites. Students will also learn about the different methods for tracking of properties of installed (used) composites.

A student knows and understands photodegradation processes of lignocellulosic materials. He/she knows contemporary materials for protection of lignocellulosic materials and surface coatings for their protection against weathering. He/she is acquainted with and understands the meaning of superhydrophobic and self-cleaning surfaces for protection of lignocellulosic elements in various constructions and objects that are exposed to weathering.

Reflections: the course is the professional fundament in accordance with the nature of the study. It represents a firm basis for further studies of properties of treated materials and surfaces and of contemporary materials and surface treatment processes.

Transferable skills: a student can use the knowledge at other technological courses. He/she knows to use scientific literature and computer data bases. Besides, he/she is acquainted with methods of scientific research work (can make a hypothesis, experimental plan, discussion, critical evaluation of the results).

Basic sources and literature

1. NAVODNIK, J. Slovenija je ustvarjena za nanotehnologije: izdelki in tehnologije prihodnosti: strokovna monografija. Celje: Navodnik, 2007. 399 str. ISBN 978-961-92027-0-8. (izbrana poglavja)

2. BULIAN, F., GRAYSTONE. J. Wood coatings : theory and practice. Amsterdam: Elsevier, 2009. 320 str. ISBN 978-0-444-52840-7. (izbrana poglavja)

3. Reinprecht, L. (2016). Wood Deterioration, Protection and Maintenance. In Wood Deterioration, Protection and Maintenance. JohnWiley & Sons, Ltd. https://doi.org/10.1002/9781119106500

4. Forest Products Laboratory – USDA. (2010). Wood Handbook: Wood as an Engineering Material. In USDA – General Technical Report.

5. Mizi, F. Et al., 2009: Performance in use and new products of wood based composites. London, Brunel University Press

6. Thoemen et al., 2010: Wood–Based Panels – An Introduction for Specialist. London, Brunel University Press

Študentom bo na razpolago tudi gradivo s predavanj in vaj v elektronski obliki. Gradivo bo objavljeno pred začetkom predavanj na spletni strani. Za izdelavo seminarskih nalog in dodatno razumevanje vsebin bodo študentje uporabili tudi svetovni splet (internet).