Vpliv izpostavitve zgoščenega lesa topola in duglazije glivam razkrojevalkam na mehanske lastnosti, barvo in kemijske lastnosti

diplomsko delo - univerzitetni študij

Simon Eržen (Author), Milan Šernek (Reviewer), Miha Humar (Mentor), Andreja Kutnar (Co-mentor)

Abstract

Zaradi vse večje okoljske ozaveščenosti, velikih potreb po konstrukcijskem lesu in krčenju naravnih sestojev se precej pozornosti posveča iskanju novih metod za pridobivanje kakovostnega lesa za konstrukcijsko uporabo. Zgoščevanje lesa ima že dolgoletno tradicijo in znova stopa v ospredje zaradi vse večjega pomena izrabe obnovljivih virov, tudi plantažnega lesa. Zgoščen les ima boljše mehanske lastnosti od nezgoščenega iste vrste. Želeli smo preveriti, ali je mogoče zgoščen plantažni les uporabiti v konstrukcijske namene tudi v primeru izpostavitve biološkim dejavnikom. Uporabili smo zgoščen les duglazije in hibridnega topola, obdelan s termo-hidro-mehansko metodo zgoščevanja. Les obeh vrst je bil obdelan po 3 različnih postopkih zgoščevanj, ki so se razlikovali glede na temperaturo in vlažnost v komori v času mehanskega stiskanja vzorcev: 170 °C v prehodnih pogojih vodne pare (TS); 170 °C z nasičeno vodno paro (SS); 170 °C z nasičeno vodno paro (SS) ter z dodatnim segrevanjem do 200 °C (SS+PHT). Vzorce lesa smo izpostavili glivam navadne tramovke in pisane ploskocevke za obdobje 2, 4, 6 in 8 tednov in opazovali spremembe dimenzij, barve, izgube mase, mehanskih lastnosti in kemičnih sprememb. Rezultati so pokazali, da so v proučevanih postopkih zgoščevanja uporabljene temperature prenizke, in trajanje izpostavitev tem temperaturam prekratko, za izboljšanje odpornosti zgoščenega lesa proti glivam. Zato zgoščen les, izpostavljen biološkemu razkroju, brez zaščite ni ustrezen za uporabo v konstrukcijske namene.

Keywords

les;duglazija;zgoščevanje;mehanske lastnosti;barva;gostota;FTIR;Trametes versicolor;Gloeophyllum trabeum;

Data

Language:	Slovenian
Year of publishing:	2014
Typology:	2.11 - Undergraduate Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[S. Eržen]
UDC:	630842:630844.2
COBISS:	2201225
Views:	379
Downloads:	106
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Exposure of densified poplar and Douglas wood to funghus decay and its influence on mechanical, colour and chemical properties
Secondary abstract:	Due to increased environmental awareness, large demands for structural timber and shrinking natural stands, much attention is paid to finding new methods for the production of quality wood, also in structural use. Wood densification has had a long tradition, and it is again coming into focus because of the growing importance of renewable land resources, also of plantation wood. Densified wood has better mechanical properties than uncompressed wood of the same species. The thesis tries to verify if the densified plantation timber could be used for construction purposes also in the case of exposure to biological influence. Compressed Douglas fir and hybrid poplar wood were used and treated with thermo-hydro-mechanical method of densification by 3 different procedures of compression, varing according to the temperature and humidity in the chamber during the mechanical compression of samples: 170 °C in the transient conditions of water vapor (TS); 170 °C with saturated water vapor (SS); 170 °C with saturated water vapor (SS), and by further heating to 200 °C (SS+PHT). Wood specimens were exposed to Gloeophyllum trabeum and Trametes versicolor species for a period of 2, 4, 6 and 8 weeks, and the changes in dimension, colour, weight loss, mechanical properties and chemical characteristics of wood were observed. The results showed that in the studied processes the densification temperature used was too low and the duration of exposure to heat was too short for densified wood to have an improved resistance to fungi. Therefore, densified wood without an adequate protection against biological degradation is not suitable for structural use.
Secondary keywords:	wood;Douglas fir;poplar;thickening;mechanical properties;colour;thickness;FTIR;Trametes versicolor;Gloeophyllum trabeum;
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Oddelek za lesarstvo
Pages:	VIII, 51 f.
ID:	11904365