Površinska obdelava naravne in termično modificirane resonančne smrekovine : diplomsko delo

Hribar, Mateja (author), Petrič, Marko (mentor), Pohleven, Franc (comentor), Gorišek, Željko (reviewer)

Vzorce resonančne smrekovine smo termično modificirali v vakuumu pri temperaturah 170, 180 ter 190 °C in jim določili izgubo mase, ki je posledica termične obdelave. Nato smo vse vzorce, skupaj s kontrolnimi, izpostavili štirim klimam z različno relativno zračno vlažnostjo (33, 44, 65 in 88 %) in konstantno temperaturo 20 °C, ter določili adsorpcijske in desorpcijske krivulje. Pri vseh pogojih izpostavitve so termično modificirani vzorci izkazali nižje ravnovesne vlažnosti kot kontrolni. Ugotovili smo, da so sorpcijske lastnosti termično modificiranih vzorcev v tesni povezavi z izgubo mase. Večja kot je izguba mase termično modificiranega vzorca, nižja je njegova ravnovesna vlažnost. Zatem smo vse vzorce premazali s 3 različnimi premaznimi sredstvi (z 2-komponentnim poliuretanskim in uretansko-alkidnim lakom ter s 33,7 % raztopino propolisa v etanolu) ter ponovili postopek uravnovešanja pri navedenih pogojih. Izguba mase termično modificiranih vzorcev je imela večji vpliv na sorpcijske lastnosti kot pa uporabljeni površinski premazi. Na koncu smo primerjali še lastnosti (sijaj, prožnost in oprijemnost) utrjenih filmov na nemodificiranem in modificiranem lesu. Preizkušene lastnosti vseh povrsinških premazov na termično modificiranih vzorcih so bile primerljive z lastnostmi na kontrolnih (naravnih) vzorcih.

• Language: Slovenian
• Keywords: resonančna smrekovina, termična modifikacija, sorpcijske lastnosti, površinska obdelava
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [M. Hribar]
• Year: 2008
• Number of pages: XIII, 67 f., [4 f. pril.]
• PID: 20.500.12556/RUL-302
• UDC: 674.07
• COBISS.SI-ID: 1662857
• Publication date in RUL: 11.07.2014

Secondary language

• Language: English
• Title: Surface finishing of natural and thermally modified resonant spruce wood : univerzitetni študij

Abstract

The samples of resonance spruce were thermally modified in vacuum at temperatures from 170, 180 and 190 °C, and their mass losses caused by heat treatment were evaluated. All the samples, including the control ones, were exposed to four different air humidities (33, 44, 65 and 88 %) at a constant temperature of 20 °C. Then the adsorption and desorption curves were evaluated. In comparison to control samples, the thermally modified ones exhibited lower equilibrium moisture content at all conditions. It was proved that the characteristics of thermally modified samples are in close correlation with their mass losses. Higher the mass loss was, lower was the equilibrium moisture of modified wood. All samples were coated with 3 different surface coats (2-compound polyurethane and urethane-alkyd varnish, 33.7 % propolis solution in ethanol), and exposed to the same equilibrium process as mentioned above. The mass losses of thermally modified samples have stronger influence on sorption characteristics than surface coatings. The characteristics of cured surface coatings (gloss, flexibility and adhesion) on nonmodified and on modified wood were compared. The coating characteristics studied on thermally modified samples were comparable to those on the control ones.

• Keywords: resonance spruce, thermal modification, sorption characteristics, surface finishing