Vpliv časa stiskanja na trdnost lepilnega spoja iz utekočinjenega lesa : diplomski projekt

Žakelj, Luka (author), Šernek, Milan (mentor), Šega, Bogdan (reviewer)

Poleg drugih alternativ bi tudi utekočinjen les lahko v prihodnje uporabljali kot lepilo in tako pripomogli k ohranitvi čistega okolja. Proučili smo vpliv časa stiskanja na strižno trdnost lepljencev, zlepljenih z utekočinjenim lesom. Utekočinjen les smo pripravili na osnovi podatkov iz prejšnjih raziskav v masnem razmerju med lesom in etilen glikolom 1:1, z dodatkom katalizatorja (3 % mase etilen glikola). Da bi lahko proučili vpliv časa stiskanja na trdnost lepilnega spoja, smo bukove lamele stiskali 6, 9, 12, 15 in 18 min v skladu s standardom EN 12765 (2002). Preizkušance smo razžagali iz dvoslojnih bukovih lepljencev in jih nato testirali z univerzalnim testirnim strojem ZWICK/Z005. Testiranje smo opravili takoj po lepljenju in nato še po 1, 3, 7, 14 in 28 dneh. Ugotovili smo, da preizkušanci, ne glede na čas stiskanja, niso zadovoljevali zahtev standarda EN 12765 (2002). Najvišjo strižno trdnost so dosegli preizkušanci stiskani 18, 15 ter 12 min. Vsi ti preizkušanci so izkazovali dokaj konstantne lastnosti in strižna trdnost ni bila odvisna od časa stiskanja. Najvišje ocene loma po lesu lepilnega spoja (nad 85 %) so prav tako dosegli po 18 min stiskani preizkušanci; ostali preizkušanci, stiskani krajši čas, pa so izkazovali slabše lastnosti.

• Language: Slovenian
• Keywords: lepilni spoj, utekočinjen les, čas stiskanja, strižna trdnost, trajnost
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [L. Žakelj]
• Year: 2012
• Number of pages: XI, 24 f., [16] f. pril.
• PID: 20.500.12556/RUL-666
• UDC: 630*824.8
• COBISS.SI-ID: 2043017
• Publication date in RUL: 11.07.2014

Secondary language

• Language: English
• Title: Influence of pressing time on the shear strength of lap joints bonded with liquefied wood : B. Sc. thesis

Abstract

Liquefied wood is one of the alternatives that should be used in the future as an adhesive, and it should help to maintain clean environment. The influence of pressing time on specimens bonded with liquefied wood was studied as a function of time after the bonding. Liquefied wood was prepared on the basis of data from previous studies in the mass ratio between the wood and ethylene glycol 1:1; with addition of a catalyst (3 % of the weight of ethylene glycol). To study the influence of pressing time on the shear strength the beech lamellas were pressed in accordance with the regulations of EN 12765 (2002) at 5 different times: 6, 9, 12, 15 and 18 min. The specimens were sawed from 2-layer beech assemblies and then tested on the universal testing machine ZWICK/Z005. Testing was conducted immediately after the bonding and then after 1, 3, 7, 14 and 28 days. It was found out that specimens bonded together with any of pressing times did not satisfy the requirements of EN 12765 (2002) standard. Specimens bonded with pressing time of 18 min achieved the highest results in the shear strength, closely followed by the specimens bonded with pressing time of 15 and 12 min. Specimens bonded at these 3 times achieved fairly constant results, and their values did not decline as a function of time after the bonding. The bonded specimens pressed for 18 min also reached the highest estimates of wood failure of adhesive bond (over 85 %); the specimens bonded with other pressing times achieved poor results.

• Keywords: adhesive bond, liquefied wood, pressing time, shear strength, durability