Higroskopnost in dimenzijska stabilnost lesa modificiranega z derivatom imidazola : diplomsko delo

Bižal, Uroš (author), Pohleven, Franc (mentor), Gorišek, Željko (reviewer)

Preučili smo možnost kemične modifikacije bukovine (Fagus sylvatica L.), beljave smrekovine (Picea abies Karst.) ter beljave borovine (Pinus sylvestris L.) s sredstvom, katerega glavna komponenta je derivat imidazola - dihidroksidimetiloletilen sečnina (DMES). Modifikacijo smo izvedli z dvema različnima koncentracijama sredstva (5 in 20 %) pri dveh temperaturah modifikacije (150 in 170 °C). Potek reakcije in stopnjo modifikacije smo ovrednotili z odstotnim povečanjem mase (WPG). Določili smo razliko v ravnovesni vlažnosti modificiranih in kontrolnih vzorcev ter vpliv modifikacije na dimenzijsko stabilnost vzorcev (ASE). Preučili smo tudi vpliv parametrov procesa modifikacije na izpiranje sredstva iz modificiranih vzorcev(SIST EN 84) . Optimalen postopek modifikacije je postopek z 20 % raztopino sredstva (čeprav ni velikih odstopanj v primerjavi s 5 % raztopino) pri temperaturi 170 °C. Z navedenim postopkom dosežemo najmanjše izpiranje sredstva, kar kaže na to, da je premreženje pri temperaturi 170 °C boljše kot pri temperaturi 150 °C. S to metodo modifikacije smo dosegli boljšo dimenzijsko stabilnost in nižjo ravnovesno vlažnost modificiranih vzorcev v primerjavi s kontrolnimi vzorci.

• Language: Slovenian
• Keywords: modifikacija lesa, DMES, WPG, dimenzijska stabilnost, ASE
• Work type: Undergraduate thesis
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [U. Bižal]
• Year: 2008
• Number of pages: IX, 45 f.
• PID: 20.500.12556/RUL-340
• UDC: 630*841.1
• COBISS.SI-ID: 1689481
• Publication date in RUL: 11.07.2014

Secondary language

• Language: English
• Title: Hygroscopity and dimensional stability of wood modified with imidazol derivate : visokošolski strokovni študij

Abstract

Thesis investigates possibility for chemical modification of beech, spruce sapwood and pine with an agent, the main component of which is imidazol derivative - dimethyloldihydroxyethyleneurea (DMDHEU). Two different concentrations of agent (5 and 20 %) at two reaction temperatures (150 and 170°C) were used for modification. Reaction process and degree of modification were evaluated by weight percent gain (WPG). Differences in equilibrium moisture contents between modified and control samples and antishrinking efficency (ASE) were determined. Influence of modification process on leachability (SIST EN 84) of the modified samples was also investigated. Optimal results were achieved with 20 % solution and 170 °C. By the stated parameters the highest rate of agent crosslinking was observed. By this modification method we achieved better dimension stability and lower equilibrium moisture contents of modified samples compared to control samples.

• Keywords: wood modification, DMHEU, WPG, dimensional stability, ASE